mirror of https://gitee.com/bigwinds/arangodb
515 lines
19 KiB
Markdown
515 lines
19 KiB
Markdown
////////////////////////////////////////////////////////////////////////////////
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/// @startDocuBlock JSF_HTTP_API_TRAVERSAL
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/// @brief execute a server-side traversal
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///
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/// @RESTHEADER{POST /_api/traversal,executes a traversal}
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///
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/// @RESTDESCRIPTION
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/// Starts a traversal starting from a given vertex and following.
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/// edges contained in a given edgeCollection. The request must
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/// contain the following attributes.
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///
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/// @RESTBODYPARAM{startVertex,string,required,string}
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/// id of the startVertex, e.g. *"users/foo"*.
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///
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/// @RESTBODYPARAM{edgeCollection,string,optional, string}
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/// name of the collection that contains the edges.
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///
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/// @RESTBODYPARAM{graphName,string,optional,string}
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/// name of the graph that contains the edges.
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/// Either *edgeCollection* or *graphName* has to be given.
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/// In case both values are set the *graphName* is prefered.
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///
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/// @RESTBODYPARAM{filter,string,optional,string}
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/// default is to include all nodes:
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/// body (JavaScript code) of custom filter function
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/// function signature: *(config, vertex, path) -> mixed*
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/// can return four different string values:
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/// - *"exclude"* -> this vertex will not be visited.
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/// - *"prune"* -> the edges of this vertex will not be followed.
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/// - *""* or *undefined* -> visit the vertex and follow it's edges.
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/// - *Array* -> containing any combination of the above.
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/// If there is at least one *"exclude"* or *"prune"* respectivly
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/// is contained, it's effect will occur.
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///
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/// @RESTBODYPARAM{minDepth,string,optional,string}
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/// ANDed with any existing filters):
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/// visits only nodes in at least the given depth
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///
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/// @RESTBODYPARAM{maxDepth,string,optional,string}
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/// ANDed with any existing filters visits only nodes in at most the given depth
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///
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/// @RESTBODYPARAM{visitor,string,optional,string}
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/// body (JavaScript) code of custom visitor function
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/// function signature: *(config, result, vertex, path, connected) -> void*
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/// The visitor function can do anything, but its return value is ignored. To
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/// populate a result, use the *result* variable by reference. Note that the
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/// *connected* argument is only populated when the *order* attribute is set
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/// to *"preorder-expander"*.
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///
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/// @RESTBODYPARAM{direction,string,optional,string}
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/// direction for traversal
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/// - *if set*, must be either *"outbound"*, *"inbound"*, or *"any"*
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/// - *if not set*, the *expander* attribute must be specified
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///
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/// @RESTBODYPARAM{init,string,optional,string}
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/// body (JavaScript) code of custom result initialization function
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/// function signature: *(config, result) -> void*
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/// initialize any values in result with what is required
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///
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/// @RESTBODYPARAM{expander,string,optional,string}
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/// body (JavaScript) code of custom expander function
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/// *must* be set if *direction* attribute is **not** set
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/// function signature: *(config, vertex, path) -> array*
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/// expander must return an array of the connections for *vertex*
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/// each connection is an object with the attributes *edge* and *vertex*
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///
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/// @RESTBODYPARAM{sort,string,optional,string}
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/// body (JavaScript) code of a custom comparison function
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/// for the edges. The signature of this function is
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/// *(l, r) -> integer* (where l and r are edges) and must
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/// return -1 if l is smaller than, +1 if l is greater than,
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/// and 0 if l and r are equal. The reason for this is the
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/// following: The order of edges returned for a certain
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/// vertex is undefined. This is because there is no natural
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/// order of edges for a vertex with multiple connected edges.
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/// To explicitly define the order in which edges on the
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/// vertex are followed, you can specify an edge comparator
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/// function with this attribute. Note that the value here has
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/// to be a string to conform to the JSON standard, which in
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/// turn is parsed as function body on the server side. Furthermore
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/// note that this attribute is only used for the standard
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/// expanders. If you use your custom expander you have to
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/// do the sorting yourself within the expander code.
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///
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/// @RESTBODYPARAM{strategy,string,optional,string}
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/// traversal strategy can be *"depthfirst"* or *"breadthfirst"*
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///
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/// @RESTBODYPARAM{order,string,optional,string}
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/// traversal order can be *"preorder"*, *"postorder"* or *"preorder-expander"*
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///
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/// @RESTBODYPARAM{itemOrder,string,optional,string}
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/// item iteration order can be *"forward"* or *"backward"*
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///
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/// @RESTBODYPARAM{uniqueness,string,optional,string}
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/// specifies uniqueness for vertices and edges visited
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/// if set, must be an object like this:
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///
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/// *"uniqueness": {"vertices": "none"|"global"|"path", "edges": "none"|"global"|"path"}*
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///
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/// @RESTBODYPARAM{maxIterations,string,optional,string}
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/// Maximum number of iterations in each traversal. This number can be
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/// set to prevent endless loops in traversal of cyclic graphs. When a traversal performs
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/// as many iterations as the *maxIterations* value, the traversal will abort with an
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/// error. If *maxIterations* is not set, a server-defined value may be used.
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///
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/// @RESTDESCRIPTION
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///
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/// If the Traversal is successfully executed *HTTP 200* will be returned.
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/// Additionally the *result* object will be returned by the traversal.
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///
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/// For successful traversals, the returned JSON object has the
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/// following properties:
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///
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/// - *error*: boolean flag to indicate if an error occurred (*false*
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/// in this case)
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///
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/// - *code*: the HTTP status code
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///
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/// - *result*: the return value of the traversal
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///
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/// If the traversal specification is either missing or malformed, the server
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/// will respond with *HTTP 400*.
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///
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/// The body of the response will then contain a JSON object with additional error
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/// details. The object has the following attributes:
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///
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/// - *error*: boolean flag to indicate that an error occurred (*true* in this case)
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///
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/// - *code*: the HTTP status code
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///
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/// - *errorNum*: the server error number
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///
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/// - *errorMessage*: a descriptive error message
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///
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/// @RESTRETURNCODES
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///
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/// @RESTRETURNCODE{200}
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/// If the traversal is fully executed
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/// *HTTP 200* will be returned.
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///
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/// @RESTRETURNCODE{400}
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/// If the traversal specification is either missing or malformed, the server
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/// will respond with *HTTP 400*.
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///
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/// @RESTRETURNCODE{404}
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/// The server will responded with *HTTP 404* if the specified edge collection
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/// does not exist, or the specified start vertex cannot be found.
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///
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/// @RESTRETURNCODE{500}
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/// The server will responded with *HTTP 500* when an error occurs inside the
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/// traversal or if a traversal performs more than *maxIterations* iterations.
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///
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/// @EXAMPLES
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///
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/// In the following examples the underlying graph will contain five persons
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/// *Alice*, *Bob*, *Charlie*, *Dave* and *Eve*.
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/// We will have the following directed relations:
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/// - *Alice* knows *Bob*
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/// - *Bob* knows *Charlie*
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/// - *Bob* knows *Dave*
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/// - *Eve* knows *Alice*
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/// - *Eve* knows *Bob*
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///
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/// The starting vertex will always be Alice.
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///
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/// Follow only outbound edges
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///
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/// @EXAMPLE_ARANGOSH_RUN{RestTraversalOutbound}
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/// var examples = require("@arangodb/graph-examples/example-graph.js");
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/// var g = examples.loadGraph("knows_graph");
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/// var a = g.persons.document("alice")._id;
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/// var url = "/_api/traversal";
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/// var body = {
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/// "startVertex": a ,
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/// "graphName" : g.__name,
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/// "direction" : "outbound"};
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///
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/// var response = logCurlRequest('POST', url, body);
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/// assert(response.code === 200);
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///
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/// logJsonResponse(response);
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/// examples.dropGraph("knows_graph");
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/// @END_EXAMPLE_ARANGOSH_RUN
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///
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/// Follow only inbound edges
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///
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/// @EXAMPLE_ARANGOSH_RUN{RestTraversalInbound}
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/// var examples = require("@arangodb/graph-examples/example-graph.js");
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/// var g = examples.loadGraph("knows_graph");
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/// var a = g.persons.document("alice")._id;
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/// var url = "/_api/traversal";
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/// var body = { "startVertex": a,
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/// "graphName" : g.__name,
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/// "direction" : "inbound"};
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///
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/// var response = logCurlRequest('POST', url, body);
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/// assert(response.code === 200);
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///
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/// logJsonResponse(response);
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/// examples.dropGraph("knows_graph");
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/// @END_EXAMPLE_ARANGOSH_RUN
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///
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/// Follow any direction of edges
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///
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/// @EXAMPLE_ARANGOSH_RUN{RestTraversalAny}
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/// var examples = require("@arangodb/graph-examples/example-graph.js");
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/// var g = examples.loadGraph("knows_graph");
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/// var a = g.persons.document("alice")._id;
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/// var url = "/_api/traversal";
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/// var body = {
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/// startVertex: a,
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/// graphName: g.__name,
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/// direction: "any",
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/// uniqueness: {
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/// vertices: "none",
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/// edges: "global"
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/// }
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/// };
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///
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/// var response = logCurlRequest('POST', url, body);
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/// assert(response.code === 200);
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///
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/// logJsonResponse(response);
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/// examples.dropGraph("knows_graph");
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/// @END_EXAMPLE_ARANGOSH_RUN
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///
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/// Excluding *Charlie* and *Bob*
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///
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/// @EXAMPLE_ARANGOSH_RUN{RestTraversalFilterExclude}
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/// var examples = require("@arangodb/graph-examples/example-graph.js");
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/// var g = examples.loadGraph("knows_graph");
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/// var a = g.persons.document("alice")._id;
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/// var url = "/_api/traversal";
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/// var filter = 'if (vertex.name === "Bob" || '+
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/// ' vertex.name === "Charlie") {'+
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/// ' return "exclude";'+
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/// '}'+
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/// 'return;';
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///
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/// var body = {
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/// "startVertex" : a,
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/// "graphName" : g.__name,
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/// "direction" : "outbound",
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/// "filter" : filter};
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///
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/// var response = logCurlRequest('POST', url, body);
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/// assert(response.code === 200);
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///
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/// logJsonResponse(response);
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/// examples.dropGraph("knows_graph");
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/// @END_EXAMPLE_ARANGOSH_RUN
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///
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/// Do not follow edges from *Bob*
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///
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/// @EXAMPLE_ARANGOSH_RUN{RestTraversalFilterPrune}
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/// var examples = require("@arangodb/graph-examples/example-graph.js");
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/// var g = examples.loadGraph("knows_graph");
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/// var a = g.persons.document("alice")._id;
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/// var url = "/_api/traversal";
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/// var filter = 'if (vertex.name === "Bob") {'+
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/// 'return "prune";' +
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/// '}' +
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/// 'return;';
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///
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/// var body = { "startVertex": a,
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/// "graphName" : g.__name,
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/// "direction" : "outbound",
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/// "filter" : filter};
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///
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/// var response = logCurlRequest('POST', url, body);
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/// assert(response.code === 200);
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///
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/// logJsonResponse(response);
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/// examples.dropGraph("knows_graph");
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/// @END_EXAMPLE_ARANGOSH_RUN
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///
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/// Visit only nodes in a depth of at least 2
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///
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/// @EXAMPLE_ARANGOSH_RUN{RestTraversalMinDepth}
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/// var examples = require("@arangodb/graph-examples/example-graph.js");
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/// var g = examples.loadGraph("knows_graph");
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/// var a = g.persons.document("alice")._id;
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/// var url = "/_api/traversal";
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/// var body = { "startVertex": a,
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/// "graphName" : g.__name,
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/// "direction" : "outbound",
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/// "minDepth" : 2};
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///
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/// var response = logCurlRequest('POST', url, body);
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/// assert(response.code === 200);
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///
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/// logJsonResponse(response);
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/// examples.dropGraph("knows_graph");
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/// @END_EXAMPLE_ARANGOSH_RUN
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///
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/// Visit only nodes in a depth of at most 1
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///
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/// @EXAMPLE_ARANGOSH_RUN{RestTraversalMaxDepth}
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/// var examples = require("@arangodb/graph-examples/example-graph.js");
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/// var g = examples.loadGraph("knows_graph");
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/// var a = g.persons.document("alice")._id;
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/// var url = "/_api/traversal";
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/// var body = { "startVertex" : a,
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/// "graphName" : g.__name,
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/// "direction" : "outbound",
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/// "maxDepth" : 1};
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///
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/// var response = logCurlRequest('POST', url, body);
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/// assert(response.code === 200);
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///
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/// logJsonResponse(response);
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/// examples.dropGraph("knows_graph");
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/// @END_EXAMPLE_ARANGOSH_RUN
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///
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/// Using a visitor function to return vertex ids only
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///
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/// @EXAMPLE_ARANGOSH_RUN{RestTraversalVisitorFunc}
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/// var examples = require("@arangodb/graph-examples/example-graph.js");
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/// var g = examples.loadGraph("knows_graph");
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/// var a = g.persons.document("alice")._id;
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/// var url = "/_api/traversal";
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/// var body = { "startVertex": a,
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/// "graphName" : g.__name,
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/// "direction" : "outbound",
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/// "visitor" : "result.visited.vertices.push(vertex._id);"};
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///
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/// var response = logCurlRequest('POST', url, body);
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/// assert(response.code === 200);
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///
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/// logJsonResponse(response);
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/// examples.dropGraph("knows_graph");
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/// @END_EXAMPLE_ARANGOSH_RUN
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///
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/// Count all visited nodes and return a list of nodes only
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///
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/// @EXAMPLE_ARANGOSH_RUN{RestTraversalVisitorCountAndList}
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/// var examples = require("@arangodb/graph-examples/example-graph.js");
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/// var g = examples.loadGraph("knows_graph");
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/// var a = g.persons.document("alice")._id;
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/// var url = "/_api/traversal";
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/// var body = { "startVertex": a,
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/// "graphName" : g.__name,
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/// "direction" : "outbound",
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/// "init" : "result.visited = 0; result.myVertices = [ ];",
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/// "visitor" : "result.visited++; result.myVertices.push(vertex);"};
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///
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/// var response = logCurlRequest('POST', url, body);
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/// assert(response.code === 200);
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///
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/// logJsonResponse(response);
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/// examples.dropGraph("knows_graph");
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/// @END_EXAMPLE_ARANGOSH_RUN
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///
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/// Expand only inbound edges of *Alice* and outbound edges of *Eve*
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///
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/// @EXAMPLE_ARANGOSH_RUN{RestTraversalVisitorExpander}
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/// var examples = require("@arangodb/graph-examples/example-graph.js");
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/// var g = examples.loadGraph("knows_graph");
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/// var a = g.persons.document("alice")._id;
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/// var url = "/_api/traversal";
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/// var body = {
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/// startVertex: a,
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/// graphName: g.__name,
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/// expander: "var connections = [ ];" +
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/// "if (vertex.name === \"Alice\") {" +
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/// "config.datasource.getInEdges(vertex).forEach(function (e) {" +
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/// "connections.push({ " +
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/// "vertex: require(\"internal\").db._document(e._from), " +
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/// "edge: e" +
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/// "});" +
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/// "});" +
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/// "}" +
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/// "if (vertex.name === \"Eve\") {" +
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/// "config.datasource.getOutEdges(vertex).forEach(function (e) {" +
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/// "connections.push({" +
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/// "vertex: require(\"internal\").db._document(e._to), " +
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/// "edge: e" +
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/// "});" +
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/// "});" +
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/// "}" +
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/// "return connections;"
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/// };
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///
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/// var response = logCurlRequest('POST', url, body);
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/// assert(response.code === 200);
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///
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/// logJsonResponse(response);
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/// examples.dropGraph("knows_graph");
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/// @END_EXAMPLE_ARANGOSH_RUN
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///
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/// Follow the *depthfirst* strategy
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///
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/// @EXAMPLE_ARANGOSH_RUN{RestTraversalDepthFirst}
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/// var examples = require("@arangodb/graph-examples/example-graph.js");
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/// var g = examples.loadGraph("knows_graph");
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/// var a = g.persons.document("alice")._id;
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/// var url = "/_api/traversal";
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/// var body = {
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/// startVertex: a,
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/// graphName: g.__name,
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/// direction: "any",
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/// strategy: "depthfirst"
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/// };
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///
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/// var response = logCurlRequest('POST', url, body);
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/// assert(response.code === 200);
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///
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/// logJsonResponse(response);
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/// examples.dropGraph("knows_graph");
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/// @END_EXAMPLE_ARANGOSH_RUN
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///
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/// Using *postorder* ordering
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///
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/// @EXAMPLE_ARANGOSH_RUN{RestTraversalPostorder}
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/// var examples = require("@arangodb/graph-examples/example-graph.js");
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/// var g = examples.loadGraph("knows_graph");
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/// var a = g.persons.document("alice")._id;
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/// var url = "/_api/traversal";
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/// var body = {
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/// startVertex: a,
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/// graphName: g.__name,
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/// direction: "any",
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/// order: "postorder"
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/// };
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///
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/// var response = logCurlRequest('POST', url, body);
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/// assert(response.code === 200);
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///
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/// logJsonResponse(response);
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/// examples.dropGraph("knows_graph");
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/// @END_EXAMPLE_ARANGOSH_RUN
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///
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/// Using *backward* item-ordering:
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///
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/// @EXAMPLE_ARANGOSH_RUN{RestTraversalBackwardItemOrder}
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/// var examples = require("@arangodb/graph-examples/example-graph.js");
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/// var g = examples.loadGraph("knows_graph");
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/// var a = g.persons.document("alice")._id;
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/// var url = "/_api/traversal";
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/// var body = {
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/// startVertex: a,
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/// graphName: g.__name,
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/// direction: "any",
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/// itemOrder: "backward"
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/// };
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///
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/// var response = logCurlRequest('POST', url, body);
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/// assert(response.code === 200);
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///
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/// logJsonResponse(response);
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/// examples.dropGraph("knows_graph");
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/// @END_EXAMPLE_ARANGOSH_RUN
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///
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/// Edges should only be included once globally,
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/// but nodes are included every time they are visited
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///
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/// @EXAMPLE_ARANGOSH_RUN{RestTraversalEdgeUniqueness}
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/// var examples = require("@arangodb/graph-examples/example-graph.js");
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/// var g = examples.loadGraph("knows_graph");
|
|
/// var a = g.persons.document("alice")._id;
|
|
/// var url = "/_api/traversal";
|
|
/// var body = {
|
|
/// startVertex: a,
|
|
/// graphName: g.__name,
|
|
/// direction: "any",
|
|
/// uniqueness: {
|
|
/// vertices: "none",
|
|
/// edges: "global"
|
|
/// }
|
|
/// };
|
|
///
|
|
/// var response = logCurlRequest('POST', url, body);
|
|
/// assert(response.code === 200);
|
|
///
|
|
/// logJsonResponse(response);
|
|
/// examples.dropGraph("knows_graph");
|
|
/// @END_EXAMPLE_ARANGOSH_RUN
|
|
///
|
|
/// If the underlying graph is cyclic, *maxIterations* should be set
|
|
///
|
|
/// The underlying graph has two vertices *Alice* and *Bob*.
|
|
/// With the directed edges:
|
|
/// - *Alice* knows *Bob*
|
|
/// _ *Bob* knows *Alice*
|
|
///
|
|
///
|
|
/// @EXAMPLE_ARANGOSH_RUN{RestTraversalMaxIterations}
|
|
/// var examples = require("@arangodb/graph-examples/example-graph.js");
|
|
/// var g = examples.loadGraph("knows_graph");
|
|
/// var a = g.persons.document("alice")._id;
|
|
/// var b = g.persons.document("bob")._id;
|
|
/// g.knows.truncate();
|
|
/// g.knows.save(a, b, {});
|
|
/// g.knows.save(b, a, {});
|
|
/// var url = "/_api/traversal";
|
|
/// var body = {
|
|
/// startVertex: a,
|
|
/// graphName: g.__name,
|
|
/// direction: "any",
|
|
/// uniqueness: {
|
|
/// vertices: "none",
|
|
/// edges: "none"
|
|
/// },
|
|
/// maxIterations: 5
|
|
/// };
|
|
///
|
|
/// var response = logCurlRequest('POST', url, body);
|
|
/// assert(response.code === 500);
|
|
///
|
|
/// logJsonResponse(response);
|
|
/// examples.dropGraph("knows_graph");
|
|
/// @END_EXAMPLE_ARANGOSH_RUN
|
|
///
|
|
/// @endDocuBlock
|
|
//////////////////////////////////////////////////////////////////////////////// |