request-monitor
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JavaScript
/**
* headers.js
*
* Headers class offers convenient helpers
*/
const invalidTokenRegex = /[^\^_`a-zA-Z\-0-9!#$%&'*+.|~]/;
const invalidHeaderCharRegex = /[^\t\x20-\x7e\x80-\xff]/;
function validateName(name) {
name = `${name}`;
if (invalidTokenRegex.test(name) || name === '') {
throw new TypeError(`${name} is not a legal HTTP header name`);
}
}
function validateValue(value) {
value = `${value}`;
if (invalidHeaderCharRegex.test(value)) {
throw new TypeError(`${value} is not a legal HTTP header value`);
}
}
/**
* Find the key in the map object given a header name.
*
* Returns undefined if not found.
*
* @param String name Header name
* @return String|Undefined
*/
function find(map, name) {
name = name.toLowerCase();
for (const key in map) {
if (key.toLowerCase() === name) {
return key;
}
}
return undefined;
}
const MAP = Symbol('map');
export default class Headers {
/**
* Headers class
*
* @param Object headers Response headers
* @return Void
*/
constructor(init = undefined) {
this[MAP] = Object.create(null);
if (init instanceof Headers) {
const rawHeaders = init.raw();
const headerNames = Object.keys(rawHeaders);
for (const headerName of headerNames) {
for (const value of rawHeaders[headerName]) {
this.append(headerName, value);
}
}
return;
}
// We don't worry about converting prop to ByteString here as append()
// will handle it.
if (init == null) {
// no op
} else if (typeof init === 'object') {
const method = init[Symbol.iterator];
if (method != null) {
if (typeof method !== 'function') {
throw new TypeError('Header pairs must be iterable');
}
// sequence<sequence<ByteString>>
// Note: per spec we have to first exhaust the lists then process them
const pairs = [];
for (const pair of init) {
if (typeof pair !== 'object' || typeof pair[Symbol.iterator] !== 'function') {
throw new TypeError('Each header pair must be iterable');
}
pairs.push(Array.from(pair));
}
for (const pair of pairs) {
if (pair.length !== 2) {
throw new TypeError('Each header pair must be a name/value tuple');
}
this.append(pair[0], pair[1]);
}
} else {
// record<ByteString, ByteString>
for (const key of Object.keys(init)) {
const value = init[key];
this.append(key, value);
}
}
} else {
throw new TypeError('Provided initializer must be an object');
}
}
/**
* Return combined header value given name
*
* @param String name Header name
* @return Mixed
*/
get(name) {
name = `${name}`;
validateName(name);
const key = find(this[MAP], name);
if (key === undefined) {
return null;
}
return this[MAP][key].join(', ');
}
/**
* Iterate over all headers
*
* @param Function callback Executed for each item with parameters (value, name, thisArg)
* @param Boolean thisArg `this` context for callback function
* @return Void
*/
forEach(callback, thisArg = undefined) {
let pairs = getHeaders(this);
let i = 0;
while (i < pairs.length) {
const [name, value] = pairs[i];
callback.call(thisArg, value, name, this);
pairs = getHeaders(this);
i++;
}
}
/**
* Overwrite header values given name
*
* @param String name Header name
* @param String value Header value
* @return Void
*/
set(name, value) {
name = `${name}`;
value = `${value}`;
validateName(name);
validateValue(value);
const key = find(this[MAP], name);
this[MAP][key !== undefined ? key : name] = [value];
}
/**
* Append a value onto existing header
*
* @param String name Header name
* @param String value Header value
* @return Void
*/
append(name, value) {
name = `${name}`;
value = `${value}`;
validateName(name);
validateValue(value);
const key = find(this[MAP], name);
if (key !== undefined) {
this[MAP][key].push(value);
} else {
this[MAP][name] = [value];
}
}
/**
* Check for header name existence
*
* @param String name Header name
* @return Boolean
*/
has(name) {
name = `${name}`;
validateName(name);
return find(this[MAP], name) !== undefined;
}
/**
* Delete all header values given name
*
* @param String name Header name
* @return Void
*/
delete(name) {
name = `${name}`;
validateName(name);
const key = find(this[MAP], name);
if (key !== undefined) {
delete this[MAP][key];
}
};
/**
* Return raw headers (non-spec api)
*
* @return Object
*/
raw() {
return this[MAP];
}
/**
* Get an iterator on keys.
*
* @return Iterator
*/
keys() {
return createHeadersIterator(this, 'key');
}
/**
* Get an iterator on values.
*
* @return Iterator
*/
values() {
return createHeadersIterator(this, 'value');
}
/**
* Get an iterator on entries.
*
* This is the default iterator of the Headers object.
*
* @return Iterator
*/
[Symbol.iterator]() {
return createHeadersIterator(this, 'key+value');
}
}
Headers.prototype.entries = Headers.prototype[Symbol.iterator];
Object.defineProperty(Headers.prototype, Symbol.toStringTag, {
value: 'Headers',
writable: false,
enumerable: false,
configurable: true
});
Object.defineProperties(Headers.prototype, {
get: { enumerable: true },
forEach: { enumerable: true },
set: { enumerable: true },
append: { enumerable: true },
has: { enumerable: true },
delete: { enumerable: true },
keys: { enumerable: true },
values: { enumerable: true },
entries: { enumerable: true }
});
function getHeaders(headers, kind = 'key+value') {
const keys = Object.keys(headers[MAP]).sort();
return keys.map(
kind === 'key' ?
k => k.toLowerCase() :
kind === 'value' ?
k => headers[MAP][k].join(', ') :
k => [k.toLowerCase(), headers[MAP][k].join(', ')]
);
}
const INTERNAL = Symbol('internal');
function createHeadersIterator(target, kind) {
const iterator = Object.create(HeadersIteratorPrototype);
iterator[INTERNAL] = {
target,
kind,
index: 0
};
return iterator;
}
const HeadersIteratorPrototype = Object.setPrototypeOf({
next() {
// istanbul ignore if
if (!this ||
Object.getPrototypeOf(this) !== HeadersIteratorPrototype) {
throw new TypeError('Value of `this` is not a HeadersIterator');
}
const {
target,
kind,
index
} = this[INTERNAL];
const values = getHeaders(target, kind);
const len = values.length;
if (index >= len) {
return {
value: undefined,
done: true
};
}
this[INTERNAL].index = index + 1;
return {
value: values[index],
done: false
};
}
}, Object.getPrototypeOf(
Object.getPrototypeOf([][Symbol.iterator]())
));
Object.defineProperty(HeadersIteratorPrototype, Symbol.toStringTag, {
value: 'HeadersIterator',
writable: false,
enumerable: false,
configurable: true
});
/**
* Export the Headers object in a form that Node.js can consume.
*
* @param Headers headers
* @return Object
*/
export function exportNodeCompatibleHeaders(headers) {
const obj = Object.assign({ __proto__: null }, headers[MAP]);
// http.request() only supports string as Host header. This hack makes
// specifying custom Host header possible.
const hostHeaderKey = find(headers[MAP], 'Host');
if (hostHeaderKey !== undefined) {
obj[hostHeaderKey] = obj[hostHeaderKey][0];
}
return obj;
}
/**
* Create a Headers object from an object of headers, ignoring those that do
* not conform to HTTP grammar productions.
*
* @param Object obj Object of headers
* @return Headers
*/
export function createHeadersLenient(obj) {
const headers = new Headers();
for (const name of Object.keys(obj)) {
if (invalidTokenRegex.test(name)) {
continue;
}
if (Array.isArray(obj[name])) {
for (const val of obj[name]) {
if (invalidHeaderCharRegex.test(val)) {
continue;
}
if (headers[MAP][name] === undefined) {
headers[MAP][name] = [val];
} else {
headers[MAP][name].push(val);
}
}
} else if (!invalidHeaderCharRegex.test(obj[name])) {
headers[MAP][name] = [obj[name]];
}
}
return headers;
}