mirror of https://gitee.com/bigwinds/arangodb
324 lines
11 KiB
JavaScript
324 lines
11 KiB
JavaScript
////////////////////////////////////////////////////////////////////////////////
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/// @brief query results cursor actions
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///
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/// @file
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///
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/// DISCLAIMER
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///
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/// Copyright 2012 triagens GmbH, Cologne, Germany
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///
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/// Licensed under the Apache License, Version 2.0 (the "License");
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/// you may not use this file except in compliance with the License.
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/// You may obtain a copy of the License at
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///
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/// http://www.apache.org/licenses/LICENSE-2.0
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///
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/// Unless required by applicable law or agreed to in writing, software
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/// distributed under the License is distributed on an "AS IS" BASIS,
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/// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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/// See the License for the specific language governing permissions and
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/// limitations under the License.
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///
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/// Copyright holder is triAGENS GmbH, Cologne, Germany
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///
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/// @author Achim Brandt
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/// @author Jan Steemann
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/// @author Copyright 2012, triAGENS GmbH, Cologne, Germany
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////////////////////////////////////////////////////////////////////////////////
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var arangodb = require("org/arangodb");
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var actions = require("org/arangodb/actions");
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var internal = require("internal");
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var ArangoError = arangodb.ArangoError;
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var QUERY = internal.AQL_QUERY;
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// -----------------------------------------------------------------------------
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// --SECTION-- global variables
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// -----------------------------------------------------------------------------
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// -----------------------------------------------------------------------------
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// --SECTION-- private functions
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// -----------------------------------------------------------------------------
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////////////////////////////////////////////////////////////////////////////////
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/// @addtogroup ArangoAPI
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/// @{
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////////////////////////////////////////////////////////////////////////////////
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////////////////////////////////////////////////////////////////////////////////
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/// @brief create a cursor and return the first results
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///
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/// @RESTHEADER{POST /_api/cursor,creates a cursor}
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///
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/// @REST{POST /_api/cursor}
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///
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/// The query details include the query string plus optional query options and
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/// bind parameters. These values need to be passed in a JSON representation in
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/// the body of the POST request.
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///
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/// The following attributes can be used inside the JSON object:
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///
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/// - `query`: contains the query string to be executed (mandatory)
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///
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/// - `count`: boolean flag that indicates whether the number of documents
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/// found should be returned as "count" attribute in the result set (optional).
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/// Calculating the "count" attribute might have a performance penalty for
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/// some queries so this option is turned off by default.
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///
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/// - `batchSize`: maximum number of result documents to be transferred from
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/// the server to the client in one roundtrip (optional). If this attribute is
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/// not set, a server-controlled default value will be used.
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///
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/// - `bindVars`: key/value list of bind parameters (optional).
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///
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/// If the result set can be created by the server, the server will respond with
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/// `HTTP 201`. The body of the response will contain a JSON object with the
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/// result set.
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///
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/// The JSON object has the following properties:
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///
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/// - `error`: boolean flag to indicate that 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`: an array of result documents (might be empty if query has no results)
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///
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/// - `hasMore`: a boolean indicator whether there are more results
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/// available on the server
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///
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/// - `count`: the total number of result documents available (only
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/// available if the query was executed with the `count` attribute set.
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///
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/// - `id`: id of temporary cursor created on the server (optional, see above)
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///
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/// If the JSON representation is malformed or the query specification is
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/// missing from the request, the server will respond with `HTTP 400`.
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///
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/// The body of the response will 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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/// If the query specification is complete, the server will process the query. If an
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/// error occurs during query processing, the server will respond with `HTTP 400`.
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/// Again, the body of the response will contain details about the error.
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///
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/// A list of query errors can be found @ref ArangoErrors here.
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///
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/// @EXAMPLES
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///
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/// Executes a query and extract the result in a single go:
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///
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/// @verbinclude api-cursor-create-for-limit-return-single
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///
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/// Bad queries:
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///
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/// @verbinclude api-cursor-missing-body
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///
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/// @verbinclude api-cursor-unknown-collection
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////////////////////////////////////////////////////////////////////////////////
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function POST_api_cursor(req, res) {
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if (req.suffix.length != 0) {
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actions.resultNotFound(req, res, arangodb.ERROR_CURSOR_NOT_FOUND);
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return;
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}
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var json = actions.getJsonBody(req, res);
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if (json === undefined) {
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actions.resultBad(req, res, arangodb.ERROR_QUERY_EMPTY);
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return;
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}
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var cursor;
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if (json.query != undefined) {
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cursor = QUERY(json.query,
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json.bindVars,
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(json.count != undefined ? json.count : false),
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json.batchSize,
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(json.batchSize == undefined));
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}
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else {
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actions.resultBad(req, res, arangodb.ERROR_QUERY_EMPTY);
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return;
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}
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// error occurred
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if (cursor instanceof Error) {
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actions.resultException(req, res, cursor);
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return;
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}
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// this might dispose or persist the cursor
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actions.resultCursor(req, res, cursor, actions.HTTP_CREATED, { countRequested: json.count ? true : false });
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}
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////////////////////////////////////////////////////////////////////////////////
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/// @brief return the next results from an existing cursor
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///
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/// @RESTHEADER{PUT /_api/cursor,reads next batch from a cursor}
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///
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/// @REST{PUT /_api/cursor/`cursor-identifier`}
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///
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/// If the cursor is still alive, returns an object with the following
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/// attributes.
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///
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/// - `id`: the `cursor-identifier`
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/// - `result`: a list of documents for the current batch
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/// - `hasMore`: `false` if this was the last batch
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/// - `count`: if present the total number of elements
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///
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/// Note that even if `hasMore` returns `true`, the next call might
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/// still return no documents. If, however, `hasMore` is `false`, then
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/// the cursor is exhausted. Once the `hasMore` attribute has a value of
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/// `false`, the client can stop.
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///
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/// The server will respond with `HTTP 200` in case of success. If the
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/// cursor identifier is ommitted or somehow invalid, the server will respond
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/// with `HTTP 404`.
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///
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/// @EXAMPLES
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///
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/// Valid request for next batch:
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///
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/// @verbinclude api-cursor-create-for-limit-return-cont
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///
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/// Missing identifier
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///
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/// @verbinclude api-cursor-missing-cursor-identifier
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///
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/// Unknown identifier
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///
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/// @verbinclude api-cursor-invalid-cursor-identifier
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////////////////////////////////////////////////////////////////////////////////
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function PUT_api_cursor (req, res) {
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if (req.suffix.length != 1) {
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actions.resultBad(req, res, arangodb.ERROR_HTTP_BAD_PARAMETER);
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return;
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}
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var cursorId = decodeURIComponent(req.suffix[0]);
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var cursor = CURSOR(cursorId);
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if (! (cursor instanceof arangodb.ArangoCursor)) {
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actions.resultBad(req, res, arangodb.ERROR_CURSOR_NOT_FOUND);
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return;
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}
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try {
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// note: this might dispose or persist the cursor
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actions.resultCursor(req, res, cursor, actions.HTTP_OK);
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}
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catch (e) {
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}
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// unuse the cursor and garbage-collect it
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cursor.unuse();
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cursor = null;
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internal.wait(0.0);
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}
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////////////////////////////////////////////////////////////////////////////////
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/// @brief dispose an existing cursor
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///
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/// @RESTHEADER{DELETE /_api/cursor,deletes a cursor}
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///
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/// @REST{DELETE /_api/cursor/`cursor-identifier`}
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///
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/// Deletes the cursor and frees the resources associated with it.
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///
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/// The cursor will automatically be destroyed on the server when the client has
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/// retrieved all documents from it. The client can also explicitly destroy the
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/// cursor at any earlier time using an HTTP DELETE request. The cursor id must
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/// be included as part of the URL.
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///
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/// In case the server is aware of the cursor, it will respond with @LIT{HTTP
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/// 202}. Otherwise, it will respond with `404`.
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///
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/// Cursors that have been explicitly destroyed must not be used afterwards. If
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/// a cursor is used after it has been destroyed, the server will respond with
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/// `HTTP 404` as well.
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///
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/// Note: the server will also destroy abandoned cursors automatically after a
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/// certain server-controlled timeout to avoid resource leakage.
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///
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/// @EXAMPLES
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///
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/// @verbinclude api-cursor-delete
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////////////////////////////////////////////////////////////////////////////////
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function DELETE_api_cursor(req, res) {
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if (req.suffix.length != 1) {
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actions.resultBad(req, res, arangodb.ERROR_HTTP_BAD_PARAMETER);
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return;
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}
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var cursorId = decodeURIComponent(req.suffix[0]);
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if (! DELETE_CURSOR(cursorId)) {
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actions.resultNotFound(req, res, arangodb.ERROR_CURSOR_NOT_FOUND);
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return;
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}
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actions.resultOk(req, res, actions.HTTP_ACCEPTED, { id : cursorId });
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// we want the garbage collection to clean unused cursors immediately
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internal.wait(0.0);
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}
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// -----------------------------------------------------------------------------
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// --SECTION-- initialiser
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// -----------------------------------------------------------------------------
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////////////////////////////////////////////////////////////////////////////////
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/// @brief cursor actions gateway
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////////////////////////////////////////////////////////////////////////////////
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actions.defineHttp({
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url : "_api/cursor",
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context : "api",
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callback : function (req, res) {
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try {
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switch (req.requestType) {
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case (actions.POST) :
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POST_api_cursor(req, res);
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break;
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case (actions.PUT) :
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PUT_api_cursor(req, res);
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break;
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case (actions.DELETE) :
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DELETE_api_cursor(req, res);
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break;
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default:
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actions.resultUnsupported(req, res);
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}
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}
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catch (err) {
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actions.resultException(req, res, err);
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}
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}
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});
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////////////////////////////////////////////////////////////////////////////////
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/// @}
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////////////////////////////////////////////////////////////////////////////////
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// Local Variables:
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// mode: outline-minor
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// outline-regexp: "^\\(/// @brief\\|/// @addtogroup\\|// --SECTION--\\|/// @page\\|/// @}\\)"
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// End:
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