request-monitor
Version:
492 lines (434 loc) • 12.1 kB
JavaScript
/**
* body.js
*
* Body interface provides common methods for Request and Response
*/
import Stream from 'stream';
import Blob, { BUFFER } from './blob.js';
import FetchError from './fetch-error.js';
let convert;
try { convert = require('encoding').convert; } catch(e) {}
const INTERNALS = Symbol('Body internals');
// fix an issue where "PassThrough" isn't a named export for node <10
const PassThrough = Stream.PassThrough;
/**
* Body mixin
*
* Ref: https://fetch.spec.whatwg.org/#body
*
* @param Stream body Readable stream
* @param Object opts Response options
* @return Void
*/
export default function Body(body, {
size = 0,
timeout = 0
} = {}) {
if (body == null) {
// body is undefined or null
body = null;
} else if (isURLSearchParams(body)) {
// body is a URLSearchParams
body = Buffer.from(body.toString());
} else if (body instanceof Blob) {
// body is blob
body = body[BUFFER];
} else if (Buffer.isBuffer(body)) {
// body is Buffer
} else if (Object.prototype.toString.call(body) === '[object ArrayBuffer]') {
// body is ArrayBuffer
body = Buffer.from(body);
} else if (ArrayBuffer.isView(body)) {
// body is ArrayBufferView
body = Buffer.from(body.buffer, body.byteOffset, body.byteLength);
} else if (body instanceof Stream) {
// body is stream
} else {
// none of the above
// coerce to string then buffer
body = Buffer.from(String(body));
}
this[INTERNALS] = {
body,
disturbed: false,
error: null
};
this.size = size;
this.timeout = timeout;
if (body instanceof Stream) {
body.on('error', err => {
const error = err.name === 'AbortError'
? err
: new FetchError(`Invalid response body while trying to fetch ${this.url}: ${err.message}`, 'system', err);
this[INTERNALS].error = error;
});
}
}
Body.prototype = {
get body() {
return this[INTERNALS].body;
},
get bodyUsed() {
return this[INTERNALS].disturbed;
},
/**
* Decode response as ArrayBuffer
*
* @return Promise
*/
arrayBuffer() {
return consumeBody.call(this).then(buf => buf.buffer.slice(buf.byteOffset, buf.byteOffset + buf.byteLength));
},
/**
* Return raw response as Blob
*
* @return Promise
*/
blob() {
let ct = this.headers && this.headers.get('content-type') || '';
return consumeBody.call(this).then(buf => Object.assign(
// Prevent copying
new Blob([], {
type: ct.toLowerCase()
}),
{
[BUFFER]: buf
}
));
},
/**
* Decode response as json
*
* @return Promise
*/
json() {
return consumeBody.call(this).then((buffer) => {
try {
return JSON.parse(buffer.toString());
} catch (err) {
return Body.Promise.reject(new FetchError(`invalid json response body at ${this.url} reason: ${err.message}`, 'invalid-json'));
}
})
},
/**
* Decode response as text
*
* @return Promise
*/
text() {
return consumeBody.call(this).then(buffer => buffer.toString());
},
/**
* Decode response as buffer (non-spec api)
*
* @return Promise
*/
buffer() {
return consumeBody.call(this);
},
/**
* Decode response as text, while automatically detecting the encoding and
* trying to decode to UTF-8 (non-spec api)
*
* @return Promise
*/
textConverted() {
return consumeBody.call(this).then(buffer => convertBody(buffer, this.headers));
}
};
// In browsers, all properties are enumerable.
Object.defineProperties(Body.prototype, {
body: { enumerable: true },
bodyUsed: { enumerable: true },
arrayBuffer: { enumerable: true },
blob: { enumerable: true },
json: { enumerable: true },
text: { enumerable: true }
});
Body.mixIn = function (proto) {
for (const name of Object.getOwnPropertyNames(Body.prototype)) {
// istanbul ignore else: future proof
if (!(name in proto)) {
const desc = Object.getOwnPropertyDescriptor(Body.prototype, name);
Object.defineProperty(proto, name, desc);
}
}
};
/**
* Consume and convert an entire Body to a Buffer.
*
* Ref: https://fetch.spec.whatwg.org/#concept-body-consume-body
*
* @return Promise
*/
function consumeBody() {
if (this[INTERNALS].disturbed) {
return Body.Promise.reject(new TypeError(`body used already for: ${this.url}`));
}
this[INTERNALS].disturbed = true;
if (this[INTERNALS].error) {
return Body.Promise.reject(this[INTERNALS].error);
}
// body is null
if (this.body === null) {
return Body.Promise.resolve(Buffer.alloc(0));
}
// body is buffer
if (Buffer.isBuffer(this.body)) {
return Body.Promise.resolve(this.body);
}
// istanbul ignore if: should never happen
if (!(this.body instanceof Stream)) {
return Body.Promise.resolve(Buffer.alloc(0));
}
// body is stream
// get ready to actually consume the body
let accum = [];
let accumBytes = 0;
let abort = false;
return new Body.Promise((resolve, reject) => {
let resTimeout;
// allow timeout on slow response body
if (this.timeout) {
resTimeout = setTimeout(() => {
abort = true;
reject(new FetchError(`Response timeout while trying to fetch ${this.url} (over ${this.timeout}ms)`, 'body-timeout'));
}, this.timeout);
}
// handle stream errors
this.body.on('error', err => {
if (err.name === 'AbortError') {
// if the request was aborted, reject with this Error
abort = true;
reject(err);
} else {
// other errors, such as incorrect content-encoding
reject(new FetchError(`Invalid response body while trying to fetch ${this.url}: ${err.message}`, 'system', err));
}
});
this.body.on('data', chunk => {
if (abort || chunk === null) {
return;
}
if (this.size && accumBytes + chunk.length > this.size) {
abort = true;
reject(new FetchError(`content size at ${this.url} over limit: ${this.size}`, 'max-size'));
return;
}
accumBytes += chunk.length;
accum.push(chunk);
});
this.body.on('end', () => {
if (abort) {
return;
}
clearTimeout(resTimeout);
try {
resolve(Buffer.concat(accum));
} catch (err) {
// handle streams that have accumulated too much data (issue #414)
reject(new FetchError(`Could not create Buffer from response body for ${this.url}: ${err.message}`, 'system', err));
}
});
});
}
/**
* Detect buffer encoding and convert to target encoding
* ref: http://www.w3.org/TR/2011/WD-html5-20110113/parsing.html#determining-the-character-encoding
*
* @param Buffer buffer Incoming buffer
* @param String encoding Target encoding
* @return String
*/
function convertBody(buffer, headers) {
if (typeof convert !== 'function') {
throw new Error('The package `encoding` must be installed to use the textConverted() function');
}
const ct = headers.get('content-type');
let charset = 'utf-8';
let res, str;
// header
if (ct) {
res = /charset=([^;]*)/i.exec(ct);
}
// no charset in content type, peek at response body for at most 1024 bytes
str = buffer.slice(0, 1024).toString();
// html5
if (!res && str) {
res = /<meta.+?charset=(['"])(.+?)\1/i.exec(str);
}
// html4
if (!res && str) {
res = /<meta[\s]+?http-equiv=(['"])content-type\1[\s]+?content=(['"])(.+?)\2/i.exec(str);
if (res) {
res = /charset=(.*)/i.exec(res.pop());
}
}
// xml
if (!res && str) {
res = /<\?xml.+?encoding=(['"])(.+?)\1/i.exec(str);
}
// found charset
if (res) {
charset = res.pop();
// prevent decode issues when sites use incorrect encoding
// ref: https://hsivonen.fi/encoding-menu/
if (charset === 'gb2312' || charset === 'gbk') {
charset = 'gb18030';
}
}
// turn raw buffers into a single utf-8 buffer
return convert(
buffer,
'UTF-8',
charset
).toString();
}
/**
* Detect a URLSearchParams object
* ref: https://github.com/bitinn/node-fetch/issues/296#issuecomment-307598143
*
* @param Object obj Object to detect by type or brand
* @return String
*/
function isURLSearchParams(obj) {
// Duck-typing as a necessary condition.
if (typeof obj !== 'object' ||
typeof obj.append !== 'function' ||
typeof obj.delete !== 'function' ||
typeof obj.get !== 'function' ||
typeof obj.getAll !== 'function' ||
typeof obj.has !== 'function' ||
typeof obj.set !== 'function') {
return false;
}
// Brand-checking and more duck-typing as optional condition.
return obj.constructor.name === 'URLSearchParams' ||
Object.prototype.toString.call(obj) === '[object URLSearchParams]' ||
typeof obj.sort === 'function';
}
/**
* Clone body given Res/Req instance
*
* @param Mixed instance Response or Request instance
* @return Mixed
*/
export function clone(instance) {
let p1, p2;
let body = instance.body;
// don't allow cloning a used body
if (instance.bodyUsed) {
throw new Error('cannot clone body after it is used');
}
// check that body is a stream and not form-data object
// note: we can't clone the form-data object without having it as a dependency
if ((body instanceof Stream) && (typeof body.getBoundary !== 'function')) {
// tee instance body
p1 = new PassThrough();
p2 = new PassThrough();
body.pipe(p1);
body.pipe(p2);
// set instance body to teed body and return the other teed body
instance[INTERNALS].body = p1;
body = p2;
}
return body;
}
/**
* Performs the operation "extract a `Content-Type` value from |object|" as
* specified in the specification:
* https://fetch.spec.whatwg.org/#concept-bodyinit-extract
*
* This function assumes that instance.body is present.
*
* @param Mixed instance Response or Request instance
*/
export function extractContentType(body) {
// istanbul ignore if: Currently, because of a guard in Request, body
// can never be null. Included here for completeness.
if (body === null) {
// body is null
return null;
} else if (typeof body === 'string') {
// body is string
return 'text/plain;charset=UTF-8';
} else if (isURLSearchParams(body)) {
// body is a URLSearchParams
return 'application/x-www-form-urlencoded;charset=UTF-8';
} else if (body instanceof Blob) {
// body is blob
return body.type || null;
} else if (Buffer.isBuffer(body)) {
// body is buffer
return null;
} else if (Object.prototype.toString.call(body) === '[object ArrayBuffer]') {
// body is ArrayBuffer
return null;
} else if (ArrayBuffer.isView(body)) {
// body is ArrayBufferView
return null;
} else if (typeof body.getBoundary === 'function') {
// detect form data input from form-data module
return `multipart/form-data;boundary=${body.getBoundary()}`;
} else if (body instanceof Stream) {
// body is stream
// can't really do much about this
return null;
} else {
// Body constructor defaults other things to string
return 'text/plain;charset=UTF-8';
}
}
/**
* The Fetch Standard treats this as if "total bytes" is a property on the body.
* For us, we have to explicitly get it with a function.
*
* ref: https://fetch.spec.whatwg.org/#concept-body-total-bytes
*
* @param Body instance Instance of Body
* @return Number? Number of bytes, or null if not possible
*/
export function getTotalBytes(instance) {
const {body} = instance;
// istanbul ignore if: included for completion
if (body === null) {
// body is null
return 0;
} else if (Buffer.isBuffer(body)) {
// body is buffer
return body.length;
} else if (body && typeof body.getLengthSync === 'function') {
// detect form data input from form-data module
if (body._lengthRetrievers && body._lengthRetrievers.length == 0 || // 1.x
body.hasKnownLength && body.hasKnownLength()) { // 2.x
return body.getLengthSync();
}
return null;
} else {
// body is stream
// can't really do much about this
return null;
}
}
/**
* Write a Body to a Node.js WritableStream (e.g. http.Request) object.
*
* @param Body instance Instance of Body
* @return Void
*/
export function writeToStream(dest, instance) {
const {body} = instance;
if (body === null) {
// body is null
dest.end();
} else if (Buffer.isBuffer(body)) {
// body is buffer
dest.write(body);
dest.end()
} else {
// body is stream
body.pipe(dest);
}
}
// expose Promise
Body.Promise = global.Promise;