owltech
Version:
This a backend for OwlTech Company
205 lines • 7.85 kB
JavaScript
"use strict";
/**
* Copyright 2016, Google Inc.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following disclaimer
* in the documentation and/or other materials provided with the
* distribution.
* * Neither the name of Google Inc. nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
Object.defineProperty(exports, "__esModule", { value: true });
const warnings_1 = require("./warnings");
const duplexify = require('duplexify');
const retryRequest = require('retry-request');
/**
* The type of gRPC streaming.
* @enum {number}
*/
var StreamType;
(function (StreamType) {
/** Client sends a single request, server streams responses. */
StreamType[StreamType["SERVER_STREAMING"] = 1] = "SERVER_STREAMING";
/** Client streams requests, server returns a single response. */
StreamType[StreamType["CLIENT_STREAMING"] = 2] = "CLIENT_STREAMING";
/** Both client and server stream objects. */
StreamType[StreamType["BIDI_STREAMING"] = 3] = "BIDI_STREAMING";
})(StreamType = exports.StreamType || (exports.StreamType = {}));
class StreamProxy extends duplexify {
/**
* StreamProxy is a proxy to gRPC-streaming method.
*
* @private
* @constructor
* @param {StreamType} type - the type of gRPC stream.
* @param {ApiCallback} callback - the callback for further API call.
*/
constructor(type, callback) {
super(undefined, undefined, {
objectMode: true,
readable: type !== StreamType.CLIENT_STREAMING,
writable: type !== StreamType.SERVER_STREAMING,
});
this.type = type;
this._callback = callback;
this._isCancelCalled = false;
}
cancel() {
if (this.stream) {
this.stream.cancel();
}
else {
this._isCancelCalled = true;
}
}
/**
* Forward events from an API request stream to the user's stream.
* @param {Stream} stream - The API request stream.
*/
forwardEvents(stream) {
const eventsToForward = ['metadata', 'response', 'status'];
eventsToForward.forEach(event => {
stream.on(event, this.emit.bind(this, event));
});
// We also want to supply the status data as 'response' event to support
// the behavior of google-cloud-node expects.
// see:
// https://github.com/GoogleCloudPlatform/google-cloud-node/pull/1775#issuecomment-259141029
// https://github.com/GoogleCloudPlatform/google-cloud-node/blob/116436fa789d8b0f7fc5100b19b424e3ec63e6bf/packages/common/src/grpc-service.js#L355
stream.on('metadata', metadata => {
// Create a response object with succeeds.
// TODO: unify this logic with the decoration of gRPC response when it's
// added. see: https://github.com/googleapis/gax-nodejs/issues/65
stream.emit('response', {
code: 200,
details: '',
message: 'OK',
metadata,
});
});
}
/**
* Specifies the target stream.
* @param {ApiCall} apiCall - the API function to be called.
* @param {Object} argument - the argument to be passed to the apiCall.
*/
setStream(apiCall, argument) {
if (this.type === StreamType.SERVER_STREAMING) {
const retryStream = retryRequest(null, {
objectMode: true,
request: () => {
if (this._isCancelCalled) {
if (this.stream) {
this.stream.cancel();
}
return;
}
const stream = apiCall(argument, this._callback);
this.stream = stream;
this.forwardEvents(stream);
return stream;
},
});
this.setReadable(retryStream);
return;
}
const stream = apiCall(argument, this._callback);
this.stream = stream;
this.forwardEvents(stream);
if (this.type === StreamType.CLIENT_STREAMING) {
this.setWritable(stream);
}
if (this.type === StreamType.BIDI_STREAMING) {
this.setReadable(stream);
this.setWritable(stream);
}
if (this._isCancelCalled && this.stream) {
this.stream.cancel();
}
}
}
exports.StreamProxy = StreamProxy;
class GrpcStreamable {
/**
* An API caller for methods of gRPC streaming.
* @private
* @constructor
* @param {StreamDescriptor} descriptor - the descriptor of the method structure.
*/
constructor(descriptor) {
this.descriptor = descriptor;
}
init(settings, callback) {
return new StreamProxy(this.descriptor.type, callback);
}
wrap(func) {
switch (this.descriptor.type) {
case StreamType.SERVER_STREAMING:
return (argument, metadata, options) => {
return func(argument, metadata, options);
};
case StreamType.CLIENT_STREAMING:
return (argument, metadata, options, callback) => {
return func(metadata, options, callback);
};
case StreamType.BIDI_STREAMING:
return (argument, metadata, options) => {
return func(metadata, options);
};
default:
warnings_1.warn('streaming_wrap_unknown_stream_type', `Unknown stream type: ${this.descriptor.type}`);
}
return func;
}
call(apiCall, argument, settings, stream) {
stream.setStream(apiCall, argument);
}
fail(stream, err) {
stream.emit('error', err);
}
result(stream) {
return stream;
}
}
exports.GrpcStreamable = GrpcStreamable;
class StreamDescriptor {
/**
* Describes the structure of gRPC streaming call.
* @constructor
* @param {StreamType} streamType - the type of streaming.
*/
constructor(streamType) {
this.type = streamType;
}
apiCaller(settings) {
// Right now retrying does not work with gRPC-streaming, because retryable
// assumes an API call returns an event emitter while gRPC-streaming methods
// return Stream.
// TODO: support retrying.
settings.retry = null;
return new GrpcStreamable(this);
}
}
exports.StreamDescriptor = StreamDescriptor;
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