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arangodb/js/actions/api-traversal.js

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JavaScript

/*jslint indent: 2, nomen: true, maxlen: 100, sloppy: true, vars: true, white: true, plusplus: true, evil: true */
/*global require */
////////////////////////////////////////////////////////////////////////////////
/// @brief traversal actions
///
/// @file
///
/// DISCLAIMER
///
/// Copyright 2012 triagens GmbH, Cologne, Germany
///
/// Licensed under the Apache License, Version 2.0 (the "License");
/// you may not use this file except in compliance with the License.
/// You may obtain a copy of the License at
///
/// http://www.apache.org/licenses/LICENSE-2.0
///
/// Unless required by applicable law or agreed to in writing, software
/// distributed under the License is distributed on an "AS IS" BASIS,
/// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
/// See the License for the specific language governing permissions and
/// limitations under the License.
///
/// Copyright holder is triAGENS GmbH, Cologne, Germany
///
/// @author Jan Steemann
/// @author Copyright 2013, triAGENS GmbH, Cologne, Germany
////////////////////////////////////////////////////////////////////////////////
var arangodb = require("org/arangodb");
var actions = require("org/arangodb/actions");
var db = require("internal").db;
var traversal = require("org/arangodb/graph/traversal");
var Traverser = traversal.Traverser;
// -----------------------------------------------------------------------------
// --SECTION-- private functions
// -----------------------------------------------------------------------------
////////////////////////////////////////////////////////////////////////////////
/// @addtogroup ArangoAPI
/// @{
////////////////////////////////////////////////////////////////////////////////
////////////////////////////////////////////////////////////////////////////////
/// @brief create a "bad parameter" error
////////////////////////////////////////////////////////////////////////////////
function badParam (req, res, message) {
actions.resultBad(req,
res,
arangodb.ERROR_HTTP_BAD_PARAMETER,
message);
}
////////////////////////////////////////////////////////////////////////////////
/// @brief create a "not found" error
////////////////////////////////////////////////////////////////////////////////
function notFound (req, res, code, message) {
actions.resultNotFound(req,
res,
code,
message);
}
////////////////////////////////////////////////////////////////////////////////
/// @brief execute a server-side traversal
///
/// @RESTHEADER{POST /_api/traversal,executes a traversal}
///
/// @RESTBODYPARAM{body,string,required}
///
/// TODO:
/// startVertex: id of the startVertex, e.g. "users/foo", mandatory
/// edgeCollection: name of the collection that contains the edges, mandatory
/// filter: body (JavaScript code) of custom filter function, optional
/// function signature: (config, vertex, path) -> mixed
/// can return either undefined (=include), 'exclude', 'prune' or an array of these
/// if no filter is specified, all nodes will be included
/// minDepth: optional minDepth filter value (will be ANDed with any existing filters)
/// maxDepth: optional maxDepth filter value (will be ANDed with any existing filters)
/// visitor: body (JavaScript) code of custom visitor function, optional
/// function signature: (config, result, vertex, path) -> void
/// visitor function can do anything, but its return value is ignored. To
/// populate a result, use the "result" variable by reference
/// example: "result.visited++; result.myVertices.push(vertex);"
/// direction: direction for traversal, optional
/// if set, must be either "outbound", "inbound", or "any"
/// if not set, the "expander" attribute must be specified
/// init: body (JavaScript) code of custom result initialisation function, optional
/// function signature: (config, result) -> void
/// initialise any values in result with what is required
/// example: "result.visited = 0; result.myVertices = [ ];"
/// expander: body (JavaScript) code of custom expander function, optional
/// must be set if "direction" attribute is not set
/// function signature: (config, vertex, path) -> array
/// expander must return an array of the connections for "vertex"
/// each connection is an object with the attributes "edge" and "vertex"
/// example: "expander": "var connections = [ ]; config.edgeCollection.outEdges(vertex).forEach(function (e) { connections.push({ vertex: e._to, edge: e }); }); return connections;"
/// strategy: traversal strategy, optional
/// can be "depthfirst" or "breadthfirst"
/// order: traversal order, optional
/// can be "preorder" or "postorder"
/// itemOrder: item iteration order, optional
/// can be "forward" or "backward"
/// uniqueness: specifies uniqueness for vertices and edges visited, optional
/// if set, must be an object like this: "uniqueness": { "vertices": "none"|"global"|path", "edges": "none"|"global"|"path" }
///
/// maxIterations: Maximum number of iterations in each traversal. This number can be
/// set to prevent endless loops in traversal of cyclic graphs. When a traversal performs
/// as many iterations as the `maxIterations` value, the traversal will abort with an
/// error. If `maxIterations` is not set, a server-defined value may be used.
///
/// the "result" object will be returned by the traversal
///
/// example:
/// POST {"edgeCollection": "e", "expander": "var connections = [ ]; config.edgeCollection.outEdges(vertex).forEach(function (e) { connections.push({ vertex: e._to, edge: e }); }); return connections;", "startVertex" : "v/jan", "filter": "return undefined;", "minDepth": 0 }
///
/// @RESTDESCRIPTION
/// TODO
////////////////////////////////////////////////////////////////////////////////
function post_api_traversal(req, res) {
var json = actions.getJsonBody(req, res);
if (json === undefined) {
return badParam(req, res);
}
// check start vertex
// -----------------------------------------
if (json.startVertex === undefined ||
typeof json.startVertex !== "string") {
return badParam(req, res, "missing or invalid startVertex");
}
var doc;
try {
doc = db._document(json.startVertex);
}
catch (err) {
return notFound(req, res, arangodb.ERROR_ARANGO_DOCUMENT_NOT_FOUND, "invalid startVertex");
}
// check edge collection
// -----------------------------------------
if (json.edgeCollection === undefined ||
typeof json.edgeCollection !== "string") {
return badParam(req, res, "missing or invalid edgeCollection");
}
var edgeCollection;
try {
edgeCollection = db._collection(json.edgeCollection);
}
catch (err2) {
}
if (edgeCollection === undefined ||
edgeCollection === null) {
return notFound(req, res, arangodb.ERROR_ARANGO_COLLECTION_NOT_FOUND, "invalid edgeCollection");
}
// set up filters
// -----------------------------------------
var filters = [ ];
if (json.minDepth !== undefined) {
filters.push(traversal.minDepthFilter);
}
if (json.maxDepth !== undefined) {
filters.push(traversal.maxDepthFilter);
}
if (json.filter) {
try {
filters.push(new Function('config', 'vertex', 'path', json.filter));
}
catch (err3) {
return badParam(req, res, "invalid filter function");
}
}
// if no filter given, use the default filter (does nothing)
if (filters.length === 0) {
filters.push(traversal.visitAllFilter);
}
// set up visitor
// -----------------------------------------
var visitor;
if (json.visitor !== undefined) {
try {
visitor = new Function('config', 'result', 'vertex', 'path', json.visitor);
}
catch (err4) {
return badParam(req, res, "invalid visitor function");
}
}
else {
visitor = traversal.trackingVisitor;
}
// set up expander
// -----------------------------------------
var expander;
if (json.direction !== undefined) {
expander = json.direction;
}
else if (json.expander !== undefined) {
try {
expander = new Function('config', 'vertex', 'path', json.expander);
}
catch (err5) {
return badParam(req, res, "invalid expander function");
}
}
if (expander === undefined) {
return badParam(req, res, "missing or invalid expander");
}
// assemble config object
// -----------------------------------------
var config = {
params: json,
edgeCollection: edgeCollection,
datasource: traversal.collectionDatasourceFactory(edgeCollection),
strategy: json.strategy,
order: json.order,
itemOrder: json.itemOrder,
expander: expander,
visitor: visitor,
filter: filters,
minDepth: json.minDepth,
maxDepth: json.maxDepth,
maxIterations: json.maxIterations,
uniqueness: json.uniqueness
};
// assemble result object
// -----------------------------------------
var result = {
visited: {
vertices: [ ],
paths: [ ]
}
};
if (json.init !== undefined) {
try {
var init = new Function('result', json.init);
init(result);
}
catch (err6) {
return badParam(req, res, "invalid init function");
}
}
// run the traversal
// -----------------------------------------
var traverser;
try {
traverser = new Traverser(config);
traverser.traverse(result, doc);
actions.resultOk(req, res, actions.HTTP_OK, { result : result });
}
catch (err7) {
if (traverser === undefined) {
// error during traversal setup
return badParam(req, res, err7);
}
actions.resultException(req, res, err7, undefined, false);
}
}
////////////////////////////////////////////////////////////////////////////////
/// @}
////////////////////////////////////////////////////////////////////////////////
// -----------------------------------------------------------------------------
// --SECTION-- initialiser
// -----------------------------------------------------------------------------
////////////////////////////////////////////////////////////////////////////////
/// @brief gateway
////////////////////////////////////////////////////////////////////////////////
actions.defineHttp({
url : "_api/traversal",
context : "api",
callback : function (req, res) {
try {
switch (req.requestType) {
case actions.POST:
post_api_traversal(req, res);
break;
default:
actions.resultUnsupported(req, res);
}
}
catch (err) {
actions.resultException(req, res, err);
}
}
});
////////////////////////////////////////////////////////////////////////////////
/// @}
////////////////////////////////////////////////////////////////////////////////
// Local Variables:
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// outline-regexp: "^\\(/// @brief\\|/// @addtogroup\\|// --SECTION--\\|/// @page\\|/// @}\\)"
// End: