/
request.js
589 lines (550 loc) · 19.3 KB
/
request.js
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var AWS = require('./core');
var AcceptorStateMachine = require('./state_machine');
var inherit = AWS.util.inherit;
var fsm = new AcceptorStateMachine();
fsm.setupStates = function() {
var hardErrorStates = ['success', 'error', 'complete'];
var transition = function transition(err, done) {
try {
var self = this;
var origError = self.response.error;
self.emit(self._asm.currentState, function() {
if (self.response.error && origError != self.response.error) {
if (hardErrorStates.indexOf(this._asm.currentState) >= 0) {
this._hardError = true;
}
}
done(self.response.error);
});
} catch (e) {
this.response.error = e;
if (hardErrorStates.indexOf(this._asm.currentState) >= 0) {
this._hardError = true;
}
done(e);
}
};
this.addState('validate', 'build', 'error', transition);
this.addState('restart', 'build', 'error', function(err, done) {
err = this.response.error;
if (!err) return done();
if (!err.retryable) return done(err);
if (this.response.retryCount < this.service.config.maxRetries) {
this.response.retryCount++;
done();
} else {
done(err);
}
});
this.addState('build', 'afterBuild', 'restart', transition);
this.addState('afterBuild', 'sign', 'restart', transition);
this.addState('sign', 'send', 'retry', transition);
this.addState('retry', 'afterRetry', 'afterRetry', transition);
this.addState('afterRetry', 'sign', 'error', transition);
this.addState('send', 'validateResponse', 'retry', transition);
this.addState('validateResponse', 'extractData', 'extractError', transition);
this.addState('extractError', 'extractData', 'retry', transition);
this.addState('extractData', 'success', 'retry', transition);
this.addState('success', 'complete', 'complete', transition);
this.addState('error', 'complete', 'complete', transition);
this.addState('complete', null, 'uncaughtException', transition);
this.addState('uncaughtException', function(err, done) {
try {
AWS.SequentialExecutor.prototype.unhandledErrorCallback.call(this, err);
} catch (e) {
if (this._hardError) throw err;
}
done(err);
});
};
fsm.setupStates();
/**
* ## Asynchronous Requests
*
* All requests made through the SDK are asynchronous and use a
* callback interface. Each service method that kicks off a request
* returns an `AWS.Request` object that you can use to register
* callbacks.
*
* For example, the following service method returns the request
* object as "request", which can be used to register callbacks:
*
* ```javascript
* // request is an AWS.Request object
* var request = ec2.describeInstances();
*
* // register callbacks on request to retrieve response data
* request.on('success', function(response) {
* console.log(response.data);
* });
* ```
*
* When a request is ready to be sent, the {send} method should
* be called:
*
* ```javascript
* request.send();
* ```
*
* ## Removing Default Listeners for Events
*
* Request objects are built with default listeners for the various events,
* depending on the service type. In some cases, you may want to remove
* some built-in listeners to customize behaviour. Doing this requires
* access to the built-in listener functions, which are exposed through
* the {AWS.EventListeners.Core} namespace. For instance, you may
* want to customize the HTTP handler used when sending a request. In this
* case, you can remove the built-in listener associated with the 'send'
* event, the {AWS.EventListeners.Core.SEND} listener and add your own.
*
* ## Multiple Callbacks and Chaining
*
* You can register multiple callbacks on any request object. The
* callbacks can be registered for different events, or all for the
* same event. In addition, you can chain callback registration, for
* example:
*
* ```javascript
* request.
* on('success', function(response) {
* console.log("Success!");
* }).
* on('error', function(response) {
* console.log("Error!");
* }).
* on('complete', function(response) {
* console.log("Always!");
* }).
* send();
* ```
*
* The above example will print either "Success! Always!", or "Error! Always!",
* depending on whether the request succeeded or not.
*
* @!attribute httpRequest
* @readonly
* @!group HTTP Properties
* @return [AWS.HttpRequest] the raw HTTP request object
* containing request headers and body information
* sent by the service.
*
* @!attribute startTime
* @readonly
* @!group Operation Properties
* @return [Date] the time that the request started
*
* @!group Request Building Events
*
* @!event validate(request)
* Triggered when a request is being validated. Listeners
* should throw an error if the request should not be sent.
* @param request [Request] the request object being sent
* @see AWS.EventListeners.Core.VALIDATE_CREDENTIALS
* @see AWS.EventListeners.Core.VALIDATE_REGION
*
* @!event build(request)
* Triggered when the request payload is being built. Listeners
* should fill the necessary information to send the request
* over HTTP.
* @param (see AWS.Request~validate)
*
* @!event sign(request)
* Triggered when the request is being signed. Listeners should
* add the correct authentication headers and/or adjust the body,
* depending on the authentication mechanism being used.
* @param (see AWS.Request~validate)
*
* @!group Request Sending Events
*
* @!event send(response)
* Triggered when the request is ready to be sent. Listeners
* should call the underlying transport layer to initiate
* the sending of the request.
* @param response [Response] the response object
* @context [Request] the request object that was sent
* @see AWS.EventListeners.Core.SEND
*
* @!event retry(response)
* Triggered when a request failed and might need to be retried.
* Listeners are responsible for checking to see if the request
* is retryable, and if so, re-signing and re-sending the request.
* Information about the failure is set in the `response.error`
* property.
*
* If a listener decides that a request should not be retried,
* that listener should `throw` an error to cancel the event chain.
* Unsetting `response.error` will have no effect.
*
* @param (see AWS.Request~send)
* @context (see AWS.Request~send)
*
* @!group Data Parsing Events
*
* @!event extractError(response)
* Triggered on all non-2xx requests so that listeners can extract
* error details from the response body. Listeners to this event
* should set the `response.error` property.
* @param (see AWS.Request~send)
* @context (see AWS.Request~send)
*
* @!event extractData(response)
* Triggered in successful requests to allow listeners to
* de-serialize the response body into `response.data`.
* @param (see AWS.Request~send)
* @context (see AWS.Request~send)
*
* @!group Completion Events
*
* @!event success(response)
* Triggered when the request completed successfully.
* `response.data` will contain the response data and
* `response.error` will be null.
* @param (see AWS.Request~send)
* @context (see AWS.Request~send)
*
* @!event error(error, response)
* Triggered when an error occurs at any point during the
* request. `response.error` will contain details about the error
* that occurred. `response.data` will be null.
* @param error [Error] the error object containing details about
* the error that occurred.
* @param (see AWS.Request~send)
* @context (see AWS.Request~send)
*
* @!event complete(response)
* Triggered whenever a request cycle completes. `response.error`
* should be checked, since the request may have failed.
* @param (see AWS.Request~send)
* @context (see AWS.Request~send)
*
* @!group HTTP Events
*
* @!event httpHeaders(statusCode, headers, response)
* Triggered when headers are sent by the remote server
* @param statusCode [Integer] the HTTP response code
* @param headers [map<String,String>] the response headers
* @param (see AWS.Request~send)
* @context (see AWS.Request~send)
*
* @!event httpData(chunk, response)
* Triggered when data is sent by the remote server
* @param chunk [Buffer] the buffer data containing the next data chunk
* from the server
* @param (see AWS.Request~send)
* @context (see AWS.Request~send)
* @see AWS.EventListeners.Core.HTTP_DATA
*
* @!event httpUploadProgress(progress, response)
* Triggered when the HTTP request has uploaded more data
* @param progress [map] An object containing the `loaded` and `total` bytes
* of the request.
* @param (see AWS.Request~send)
* @context (see AWS.Request~send)
* @note This event will not be emitted in Node.js 0.8.x.
*
* @!event httpDownloadProgress(progress, response)
* Triggered when the HTTP request has downloaded more data
* @param progress [map] An object containing the `loaded` and `total` bytes
* of the request.
* @param (see AWS.Request~send)
* @context (see AWS.Request~send)
* @note This event will not be emitted in Node.js 0.8.x.
*
* @!event httpError(error, response)
* Triggered when the HTTP request failed
* @param error [Error] the error object that was thrown
* @param (see AWS.Request~send)
* @context (see AWS.Request~send)
*
* @!event httpDone(response)
* Triggered when the server is finished sending data
* @param (see AWS.Request~send)
* @context (see AWS.Request~send)
*
* @see AWS.Response
*/
AWS.Request = inherit({
/**
* Creates a request for an operation on a given service with
* a set of input parameters.
*
* @param service [AWS.Service] the service to perform the operation on
* @param operation [String] the operation to perform on the service
* @param params [Object] parameters to send to the operation.
* See the operation's documentation for the format of the
* parameters.
*/
constructor: function Request(service, operation, params) {
var endpoint = service.endpoint;
var region = service.config.region;
// global endpoints sign as us-east-1
if (service.hasGlobalEndpoint()) region = 'us-east-1';
this.service = service;
this.operation = operation;
this.params = params || {};
this.httpRequest = new AWS.HttpRequest(endpoint, region);
this.startTime = AWS.util.date.getDate();
this.response = new AWS.Response(this);
this.restartCount = 0;
this._asm = new AcceptorStateMachine(fsm.states, 'validate');
AWS.SequentialExecutor.call(this);
this.emit = this.emitEvent;
},
/**
* @!group Sending a Request
*/
/**
* @overload send(callback = null)
* Sends the request object.
*
* @callback callback function(err, data)
* If a callback is supplied, it is called when a response is returned
* from the service.
* @param err [Error] the error object returned from the request.
* Set to `null` if the request is successful.
* @param data [Object] the de-serialized data returned from
* the request. Set to `null` if a request error occurs.
* @example Sending a request with a callback
* request = s3.putObject({Bucket: 'bucket', Key: 'key'});
* request.send(function(err, data) { console.log(err, data); });
* @example Sending a request with no callback (using event handlers)
* request = s3.putObject({Bucket: 'bucket', Key: 'key'});
* request.on('complete', function(response) { ... }); // register a callback
* request.send();
*/
send: function send(callback) {
if (callback) {
this.on('complete', function (resp) {
try {
callback.call(resp, resp.error, resp.data);
} catch (e) {
resp.request._hardError = true;
throw e;
}
});
}
this.runTo();
return this.response;
},
build: function build(callback) {
this._hardError = callback ? false : true;
return this.runTo('send', callback);
},
runTo: function runTo(state, done) {
this._asm.runTo(state, done, this);
return this;
},
/**
* Aborts a request, emitting the error and complete events.
*
* @!macro nobrowser
* @example Aborting a request after sending
* var params = {
* Bucket: 'bucket', Key: 'key',
* Body: new Buffer(1024 * 1024 * 5) // 5MB payload
* };
* var request = s3.putObject(params);
* request.send(function (err, data) {
* if (err) console.log("Error:", err.code, err.message);
* else console.log(data);
* });
*
* // abort request in 1 second
* setTimeout(request.abort.bind(request), 1000);
*
* // prints "Error: RequestAbortedError Request aborted by user"
* @return [AWS.Request] the same request object, for chaining.
* @since v1.4.0
*/
abort: function abort() {
this.removeAllListeners('validateResponse');
this.removeAllListeners('extractError');
this.on('validateResponse', function addAbortedError(resp) {
resp.error = AWS.util.error(new Error('Request aborted by user'), {
code: 'RequestAbortedError', retryable: false
});
});
if (this.httpRequest.stream) { // abort HTTP stream
this.httpRequest.stream.abort();
this.httpRequest._abortCallback();
}
return this;
},
/**
* Iterates over each page of results given a pageable request, calling
* the provided callback with each page of data. After all pages have been
* retrieved, the callback is called with `null` data.
*
* @note This operation can generate multiple requests to a service.
* @example Iterating over multiple pages of objects in an S3 bucket
* var pages = 1;
* s3.listObjects().eachPage(function(err, data) {
* if (err) return;
* console.log("Page", pages++);
* console.log(data);
* });
* @callback callback function(err, data)
* Called with each page of resulting data from the request.
*
* @param err [Error] an error object, if an error occurred.
* @param data [Object] a single page of response data. If there is no
* more data, this object will be `null`.
* @return [Boolean] if the callback returns `false`, pagination will
* stop.
*
* @api experimental
* @see AWS.Request.eachItem
* @see AWS.Response.nextPage
* @since v1.4.0
*/
eachPage: function eachPage(callback) {
function wrappedCallback(response) {
var result = callback.call(response, response.error, response.data);
if (result === false) return;
if (response.hasNextPage()) {
response.nextPage().on('complete', wrappedCallback).send();
} else {
callback.call(response, null, null);
}
}
this.on('complete', wrappedCallback).send();
},
/**
* Enumerates over individual items of a request, paging the responses if
* necessary.
*
* @api experimental
* @since v1.4.0
*/
eachItem: function eachItem(callback) {
function wrappedCallback(err, data) {
if (err) return callback(err, null);
if (data === null) return callback(null, null);
var config = this.request.service.paginationConfig(this.request.operation);
var resultKey = config.resultKey;
if (Array.isArray(resultKey)) resultKey = resultKey[0];
var results = AWS.util.jamespath.query(resultKey, data);
AWS.util.arrayEach(results, function(result) {
AWS.util.arrayEach(result, function(item) { callback(null, item); });
});
}
this.eachPage(wrappedCallback);
},
/**
* @return [Boolean] whether the operation can return multiple pages of
* response data.
* @api experimental
* @see AWS.Response.eachPage
* @since v1.4.0
*/
isPageable: function isPageable() {
return this.service.paginationConfig(this.operation) ? true : false;
},
/**
* Converts the request object into a readable stream that
* can be read from or piped into a writable stream.
*
* @note The data read from a readable stream contains only
* the raw HTTP body contents.
* @example Manually reading from a stream
* request.createReadStream().on('data', function(data) {
* console.log("Got data:", data.toString());
* });
* @example Piping a request body into a file
* var out = fs.createWriteStream('/path/to/outfile.jpg');
* s3.service.getObject(params).createReadStream().pipe(out);
* @return [Stream] the readable stream object that can be piped
* or read from (by registering 'data' event listeners).
*/
createReadStream: function createReadStream() {
var streams = require('stream');
var req = this;
var stream = null;
var legacyStreams = false;
if (AWS.HttpClient.streamsApiVersion === 2) {
stream = new streams.Readable();
stream._read = function() { stream.push(''); };
} else {
stream = new streams.Stream();
stream.readable = true;
}
stream.sent = false;
stream.on('newListener', function(event) {
if (!stream.sent && (event === 'data' || event === 'readable')) {
if (event === 'data') legacyStreams = true;
stream.sent = true;
process.nextTick(function() { req.send(function() { }); });
}
});
this.on('httpHeaders', function streamHeaders(statusCode, headers, resp) {
if (statusCode < 300) {
this.httpRequest._streaming = true;
req.removeListener('httpData', AWS.EventListeners.Core.HTTP_DATA);
req.removeListener('httpError', AWS.EventListeners.Core.HTTP_ERROR);
req.on('httpError', function streamHttpError(error, resp) {
resp.error = error;
resp.error.retryable = false;
});
var httpStream = resp.httpResponse.stream;
stream.response = resp;
stream._read = function() {
var data;
/*jshint boss:true*/
while (data = httpStream.read()) {
stream.push(data);
}
stream.push('');
};
var events = ['end', 'error', (legacyStreams ? 'data' : 'readable')];
AWS.util.arrayEach(events, function(event) {
httpStream.on(event, function(arg) {
stream.emit(event, arg);
});
});
}
});
this.on('error', function(err) {
stream.emit('error', err);
});
return stream;
},
/**
* @param [Array,Response] args This should be the response object,
* or an array of args to send to the event.
* @api private
*/
emitEvent: function emit(eventName, args, done) {
if (typeof args === 'function') { done = args; args = null; }
if (!done) done = this.unhandledErrorCallback;
if (!args) args = this.eventParameters(eventName, this.response);
var origEmit = AWS.SequentialExecutor.prototype.emit;
origEmit.call(this, eventName, args, function (err) {
if (err) this.response.error = err;
done.call(this, err);
});
},
/**
* @api private
*/
eventParameters: function eventParameters(eventName) {
switch (eventName) {
case 'validate':
case 'sign':
case 'build':
case 'afterBuild':
return [this];
case 'error':
return [this.response.error, this.response];
default:
return [this.response];
}
},
retryDelay: function retryDelay(response) {
var delay = 0;
if (!response.error.redirect) {
delay = this.service.retryDelays()[response.retryCount-1] || 0;
}
return delay;
}
});
AWS.util.mixin(AWS.Request, AWS.SequentialExecutor);