434 lines
13 KiB
JavaScript
434 lines
13 KiB
JavaScript
var url = require("url");
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var URL = url.URL;
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var http = require("http");
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var https = require("https");
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var assert = require("assert");
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var Writable = require("stream").Writable;
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var debug = require("debug")("follow-redirects");
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// RFC7231§4.2.1: Of the request methods defined by this specification,
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// the GET, HEAD, OPTIONS, and TRACE methods are defined to be safe.
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var SAFE_METHODS = { GET: true, HEAD: true, OPTIONS: true, TRACE: true };
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// Create handlers that pass events from native requests
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var eventHandlers = Object.create(null);
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["abort", "aborted", "error", "socket", "timeout"].forEach(function (event) {
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eventHandlers[event] = function (arg) {
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this._redirectable.emit(event, arg);
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};
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});
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// An HTTP(S) request that can be redirected
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function RedirectableRequest(options, responseCallback) {
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// Initialize the request
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Writable.call(this);
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options.headers = options.headers || {};
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this._options = options;
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this._ended = false;
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this._ending = false;
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this._redirectCount = 0;
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this._redirects = [];
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this._requestBodyLength = 0;
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this._requestBodyBuffers = [];
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// Since http.request treats host as an alias of hostname,
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// but the url module interprets host as hostname plus port,
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// eliminate the host property to avoid confusion.
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if (options.host) {
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// Use hostname if set, because it has precedence
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if (!options.hostname) {
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options.hostname = options.host;
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}
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delete options.host;
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}
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// Attach a callback if passed
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if (responseCallback) {
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this.on("response", responseCallback);
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}
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// React to responses of native requests
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var self = this;
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this._onNativeResponse = function (response) {
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self._processResponse(response);
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};
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// Complete the URL object when necessary
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if (!options.pathname && options.path) {
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var searchPos = options.path.indexOf("?");
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if (searchPos < 0) {
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options.pathname = options.path;
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}
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else {
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options.pathname = options.path.substring(0, searchPos);
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options.search = options.path.substring(searchPos);
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}
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}
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// Perform the first request
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this._performRequest();
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}
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RedirectableRequest.prototype = Object.create(Writable.prototype);
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// Writes buffered data to the current native request
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RedirectableRequest.prototype.write = function (data, encoding, callback) {
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// Writing is not allowed if end has been called
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if (this._ending) {
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throw new Error("write after end");
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}
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// Validate input and shift parameters if necessary
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if (!(typeof data === "string" || typeof data === "object" && ("length" in data))) {
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throw new Error("data should be a string, Buffer or Uint8Array");
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}
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if (typeof encoding === "function") {
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callback = encoding;
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encoding = null;
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}
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// Ignore empty buffers, since writing them doesn't invoke the callback
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// https://github.com/nodejs/node/issues/22066
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if (data.length === 0) {
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if (callback) {
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callback();
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}
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return;
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}
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// Only write when we don't exceed the maximum body length
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if (this._requestBodyLength + data.length <= this._options.maxBodyLength) {
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this._requestBodyLength += data.length;
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this._requestBodyBuffers.push({ data: data, encoding: encoding });
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this._currentRequest.write(data, encoding, callback);
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}
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// Error when we exceed the maximum body length
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else {
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this.emit("error", new Error("Request body larger than maxBodyLength limit"));
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this.abort();
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}
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};
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// Ends the current native request
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RedirectableRequest.prototype.end = function (data, encoding, callback) {
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// Shift parameters if necessary
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if (typeof data === "function") {
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callback = data;
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data = encoding = null;
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}
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else if (typeof encoding === "function") {
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callback = encoding;
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encoding = null;
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}
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// Write data if needed and end
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if (!data) {
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this._ended = this._ending = true;
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this._currentRequest.end(null, null, callback);
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}
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else {
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var self = this;
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var currentRequest = this._currentRequest;
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this.write(data, encoding, function () {
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self._ended = true;
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currentRequest.end(null, null, callback);
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});
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this._ending = true;
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}
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};
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// Sets a header value on the current native request
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RedirectableRequest.prototype.setHeader = function (name, value) {
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this._options.headers[name] = value;
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this._currentRequest.setHeader(name, value);
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};
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// Clears a header value on the current native request
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RedirectableRequest.prototype.removeHeader = function (name) {
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delete this._options.headers[name];
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this._currentRequest.removeHeader(name);
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};
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// Global timeout for all underlying requests
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RedirectableRequest.prototype.setTimeout = function (msecs, callback) {
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if (callback) {
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this.once("timeout", callback);
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}
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if (this.socket) {
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startTimer(this, msecs);
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}
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else {
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var self = this;
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this._currentRequest.once("socket", function () {
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startTimer(self, msecs);
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});
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}
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this.once("response", clearTimer);
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this.once("error", clearTimer);
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return this;
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};
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function startTimer(request, msecs) {
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clearTimeout(request._timeout);
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request._timeout = setTimeout(function () {
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request.emit("timeout");
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}, msecs);
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}
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function clearTimer() {
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clearTimeout(this._timeout);
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}
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// Proxy all other public ClientRequest methods
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[
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"abort", "flushHeaders", "getHeader",
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"setNoDelay", "setSocketKeepAlive",
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].forEach(function (method) {
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RedirectableRequest.prototype[method] = function (a, b) {
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return this._currentRequest[method](a, b);
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};
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});
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// Proxy all public ClientRequest properties
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["aborted", "connection", "socket"].forEach(function (property) {
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Object.defineProperty(RedirectableRequest.prototype, property, {
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get: function () { return this._currentRequest[property]; },
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});
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});
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// Executes the next native request (initial or redirect)
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RedirectableRequest.prototype._performRequest = function () {
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// Load the native protocol
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var protocol = this._options.protocol;
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var nativeProtocol = this._options.nativeProtocols[protocol];
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if (!nativeProtocol) {
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this.emit("error", new Error("Unsupported protocol " + protocol));
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return;
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}
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// If specified, use the agent corresponding to the protocol
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// (HTTP and HTTPS use different types of agents)
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if (this._options.agents) {
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var scheme = protocol.substr(0, protocol.length - 1);
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this._options.agent = this._options.agents[scheme];
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}
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// Create the native request
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var request = this._currentRequest =
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nativeProtocol.request(this._options, this._onNativeResponse);
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this._currentUrl = url.format(this._options);
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// Set up event handlers
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request._redirectable = this;
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for (var event in eventHandlers) {
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/* istanbul ignore else */
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if (event) {
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request.on(event, eventHandlers[event]);
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}
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}
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// End a redirected request
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// (The first request must be ended explicitly with RedirectableRequest#end)
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if (this._isRedirect) {
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// Write the request entity and end.
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var i = 0;
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var self = this;
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var buffers = this._requestBodyBuffers;
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(function writeNext(error) {
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// Only write if this request has not been redirected yet
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/* istanbul ignore else */
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if (request === self._currentRequest) {
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// Report any write errors
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/* istanbul ignore if */
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if (error) {
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self.emit("error", error);
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}
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// Write the next buffer if there are still left
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else if (i < buffers.length) {
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var buffer = buffers[i++];
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/* istanbul ignore else */
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if (!request.finished) {
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request.write(buffer.data, buffer.encoding, writeNext);
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}
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}
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// End the request if `end` has been called on us
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else if (self._ended) {
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request.end();
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}
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}
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}());
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}
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};
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// Processes a response from the current native request
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RedirectableRequest.prototype._processResponse = function (response) {
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// Store the redirected response
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if (this._options.trackRedirects) {
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this._redirects.push({
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url: this._currentUrl,
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headers: response.headers,
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statusCode: response.statusCode,
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});
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}
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// RFC7231§6.4: The 3xx (Redirection) class of status code indicates
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// that further action needs to be taken by the user agent in order to
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// fulfill the request. If a Location header field is provided,
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// the user agent MAY automatically redirect its request to the URI
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// referenced by the Location field value,
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// even if the specific status code is not understood.
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var location = response.headers.location;
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if (location && this._options.followRedirects !== false &&
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response.statusCode >= 300 && response.statusCode < 400) {
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// Abort the current request
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this._currentRequest.removeAllListeners();
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this._currentRequest.on("error", noop);
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this._currentRequest.abort();
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// RFC7231§6.4: A client SHOULD detect and intervene
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// in cyclical redirections (i.e., "infinite" redirection loops).
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if (++this._redirectCount > this._options.maxRedirects) {
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this.emit("error", new Error("Max redirects exceeded."));
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return;
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}
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// RFC7231§6.4: Automatic redirection needs to done with
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// care for methods not known to be safe […],
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// since the user might not wish to redirect an unsafe request.
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// RFC7231§6.4.7: The 307 (Temporary Redirect) status code indicates
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// that the target resource resides temporarily under a different URI
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// and the user agent MUST NOT change the request method
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// if it performs an automatic redirection to that URI.
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var header;
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var headers = this._options.headers;
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if (response.statusCode !== 307 && !(this._options.method in SAFE_METHODS)) {
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this._options.method = "GET";
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// Drop a possible entity and headers related to it
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this._requestBodyBuffers = [];
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for (header in headers) {
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if (/^content-/i.test(header)) {
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delete headers[header];
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}
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}
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}
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// Drop the Host header, as the redirect might lead to a different host
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if (!this._isRedirect) {
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for (header in headers) {
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if (/^host$/i.test(header)) {
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delete headers[header];
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}
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}
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}
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// Perform the redirected request
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var redirectUrl = url.resolve(this._currentUrl, location);
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debug("redirecting to", redirectUrl);
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Object.assign(this._options, url.parse(redirectUrl));
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this._isRedirect = true;
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this._performRequest();
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// Discard the remainder of the response to avoid waiting for data
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response.destroy();
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}
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else {
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// The response is not a redirect; return it as-is
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response.responseUrl = this._currentUrl;
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response.redirects = this._redirects;
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this.emit("response", response);
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// Clean up
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this._requestBodyBuffers = [];
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}
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};
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// Wraps the key/value object of protocols with redirect functionality
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function wrap(protocols) {
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// Default settings
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var exports = {
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maxRedirects: 21,
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maxBodyLength: 10 * 1024 * 1024,
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};
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// Wrap each protocol
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var nativeProtocols = {};
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Object.keys(protocols).forEach(function (scheme) {
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var protocol = scheme + ":";
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var nativeProtocol = nativeProtocols[protocol] = protocols[scheme];
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var wrappedProtocol = exports[scheme] = Object.create(nativeProtocol);
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// Executes a request, following redirects
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wrappedProtocol.request = function (input, options, callback) {
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// Parse parameters
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if (typeof input === "string") {
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var urlStr = input;
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try {
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input = urlToOptions(new URL(urlStr));
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}
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catch (err) {
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/* istanbul ignore next */
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input = url.parse(urlStr);
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}
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}
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else if (URL && (input instanceof URL)) {
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input = urlToOptions(input);
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}
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else {
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callback = options;
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options = input;
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input = { protocol: protocol };
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}
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if (typeof options === "function") {
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callback = options;
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options = null;
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}
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// Set defaults
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options = Object.assign({
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maxRedirects: exports.maxRedirects,
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maxBodyLength: exports.maxBodyLength,
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}, input, options);
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options.nativeProtocols = nativeProtocols;
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assert.equal(options.protocol, protocol, "protocol mismatch");
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debug("options", options);
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return new RedirectableRequest(options, callback);
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};
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// Executes a GET request, following redirects
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wrappedProtocol.get = function (input, options, callback) {
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var request = wrappedProtocol.request(input, options, callback);
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request.end();
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return request;
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};
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});
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return exports;
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}
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/* istanbul ignore next */
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function noop() { /* empty */ }
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// from https://github.com/nodejs/node/blob/master/lib/internal/url.js
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function urlToOptions(urlObject) {
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var options = {
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protocol: urlObject.protocol,
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hostname: urlObject.hostname.startsWith("[") ?
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/* istanbul ignore next */
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urlObject.hostname.slice(1, -1) :
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urlObject.hostname,
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hash: urlObject.hash,
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search: urlObject.search,
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pathname: urlObject.pathname,
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path: urlObject.pathname + urlObject.search,
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href: urlObject.href,
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};
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if (urlObject.port !== "") {
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options.port = Number(urlObject.port);
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}
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return options;
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}
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// Exports
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module.exports = wrap({ http: http, https: https });
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module.exports.wrap = wrap;
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