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jstewmonsindresorhus
jstewmon
authored and
sindresorhus
committedJul 14, 2018
Add beforeRequest hook (#516)
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‎readme.md‎

Lines changed: 38 additions & 32 deletions
Original file line numberDiff line numberDiff line change
@@ -258,6 +258,24 @@ Determines if a `got.HTTPError` is thrown for error responses (non-2xx status co
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If this is disabled, requests that encounter an error status code will be resolved with the `response` instead of throwing. This may be useful if you are checking for resource availability and are expecting error responses.
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###### hooks
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Type: `Object<string, Array<Function>>`<br>
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Default: `{ beforeRequest: [] }`
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Hooks allow modifications during the request lifecycle. Hook functions may be async and are run serially.
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###### hooks.beforeRequest
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Type: `Array<Function>`<br>
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Default: `[]`
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Called with the normalized request options. Got will make no further changes to the request before it is sent. This is especially useful in conjunction with [`got.extend()`](#instances) and [`got.create()`](advanced-creation.md) when you want to create an API client that uses HMAC-signing.
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See the [AWS section](#aws) for an example.
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**Note**: Modifying the `body` is not recommended because the `content-length` header has already been computed and assigned.
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#### Streams
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**Note**: Progress events, redirect events and request/response events can also be used with promises.
@@ -626,47 +644,35 @@ got('http://unix:/var/run/docker.sock:/containers/json');
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got('unix:/var/run/docker.sock:/containers/json');
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```
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## AWS
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Requests to AWS services need to have their headers signed. This can be accomplished by using the [`aws4`](https://www.npmjs.com/package/aws4) package. This is an example for querying an ["Elasticsearch Service"](https://aws.amazon.com/elasticsearch-service/) host with a signed request.
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Requests to AWS services need to have their headers signed. This can be accomplished by using the [`aws4`](https://www.npmjs.com/package/aws4) package. This is an example for querying an ["API Gateway"](https://docs.aws.amazon.com/apigateway/api-reference/signing-requests/) with a signed request.
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```js
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const url = require('url');
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const AWS = require('aws-sdk');
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const aws4 = require('aws4');
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const got = require('got');
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const config = require('./config');
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// Reads keys from the environment or `~/.aws/credentials`. Could be a plain object.
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const awsConfig = new AWS.Config({ region: config.region });
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function request(url, options) {
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const awsOpts = {
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region: awsConfig.region,
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headers: {
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accept: 'application/json',
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'content-type': 'application/json'
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},
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method: 'GET',
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json: true
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};
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// We need to parse the URL before passing it to `got` so `aws4` can sign the request
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options = {
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...url.parse(url),
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...awsOpts,
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...options
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};
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aws4.sign(options, awsConfig.credentials);
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return got(options);
664-
}
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request(`https://${config.host}/production/users/1`);
657+
const credentials = await new AWS.CredentialProviderChain().resolvePromise();
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// Create a Got instance to use relative paths and signed requests
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const awsClient = got.extend(
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{
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baseUrl: 'https://<api-id>.execute-api.<api-region>.amazonaws.com/<stage>/',
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hooks: {
664+
beforeRequest: [
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async options => {
666+
await credentials.getPromise();
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aws4.sign(options, credentials);
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}
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]
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}
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}
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);
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request(`https://${config.host}/production/`, {
669-
// All usual `got` options
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const response = await awsClient('endpoint/path', {
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// Request-specific options
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});
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```
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‎source/index.js‎

Lines changed: 3 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -23,6 +23,9 @@ const defaults = {
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throwHttpErrors: true,
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headers: {
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'user-agent': `${pkg.name}/${pkg.version} (https://github.com/sindresorhus/got)`
26+
},
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hooks: {
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beforeRequest: []
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}
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}
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};

‎source/normalize-arguments.js‎

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Original file line numberDiff line numberDiff line change
@@ -8,6 +8,7 @@ const urlToOptions = require('./url-to-options');
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const isFormData = require('./is-form-data');
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const retryAfterStatusCodes = new Set([413, 429, 503]);
11+
const knownHookEvents = ['beforeRequest'];
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module.exports = (url, options, defaults) => {
1314
if (Reflect.has(options, 'url') || (is.object(url) && Reflect.has(url, 'url'))) {
@@ -185,5 +186,31 @@ module.exports = (url, options, defaults) => {
185186
delete options.timeout;
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}
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if (is.nullOrUndefined(options.hooks)) {
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options.hooks = {};
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}
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if (is.object(options.hooks)) {
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for (const hookEvent of knownHookEvents) {
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const hooks = options.hooks[hookEvent];
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if (is.nullOrUndefined(hooks)) {
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options.hooks[hookEvent] = [];
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} else if (is.array(hooks)) {
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hooks.forEach(
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(hook, index) => {
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if (!is.function_(hook)) {
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throw new TypeError(
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`Parameter \`hooks.${hookEvent}[${index}]\` must be a function, not ${is(hook)}`
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);
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}
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}
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);
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} else {
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throw new TypeError(`Parameter \`hooks.${hookEvent}\` must be an array, not ${is(hooks)}`);
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}
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}
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} else {
212+
throw new TypeError(`Parameter \`hooks\` must be an object, not ${is(options.hooks)}`);
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}
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188215
return options;
189216
};

‎source/request-as-event-emitter.js‎

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Original file line numberDiff line numberDiff line change
@@ -241,6 +241,11 @@ module.exports = (options = {}) => {
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options.headers['content-length'] = uploadBodySize;
242242
}
243243

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for (const hook of options.hooks.beforeRequest) {
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// eslint-disable-next-line no-await-in-loop
246+
await hook(options);
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}
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get(options);
245250
} catch (error) {
246251
emitter.emit('error', error);

‎test/arguments.js‎

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Original file line numberDiff line numberDiff line change
@@ -101,6 +101,40 @@ test('throws TypeError when `url` is passed as an option', async t => {
101101
await t.throws(got({url: 'example.com'}), {instanceOf: TypeError});
102102
});
103103

104+
test('throws TypeError when `hooks` is not an object', async t => {
105+
await t.throws(
106+
() => got(s.url, {hooks: 'not object'}),
107+
{
108+
instanceOf: TypeError,
109+
message: 'Parameter `hooks` must be an object, not string'
110+
}
111+
);
112+
});
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114+
test('throws TypeError when known `hooks` value is not an array', async t => {
115+
await t.throws(
116+
() => got(s.url, {hooks: {beforeRequest: {}}}),
117+
{
118+
instanceOf: TypeError,
119+
message: 'Parameter `hooks.beforeRequest` must be an array, not Object'
120+
}
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);
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});
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124+
test('throws TypeError when known `hooks` array item is not a function', async t => {
125+
await t.throws(
126+
() => got(s.url, {hooks: {beforeRequest: [{}]}}),
127+
{
128+
instanceOf: TypeError,
129+
message: 'Parameter `hooks.beforeRequest[0]` must be a function, not Object'
130+
}
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);
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});
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test('allows extra keys in `hooks`', async t => {
135+
await t.notThrows(() => got(`${s.url}/test`, {hooks: {extra: {}}}));
136+
});
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104138
test.after('cleanup', async () => {
105139
await s.close();
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});

‎test/hooks.js‎

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Original file line numberDiff line numberDiff line change
@@ -0,0 +1,105 @@
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import test from 'ava';
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import delay from 'delay';
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import {createServer} from './helpers/server';
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import got from '..';
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let s;
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8+
test.before('setup', async () => {
9+
s = await createServer();
10+
const echoHeaders = (req, res) => {
11+
res.statusCode = 200;
12+
res.write(JSON.stringify(req.headers));
13+
res.end();
14+
};
15+
s.on('/', echoHeaders);
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await s.listen(s.port);
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});
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test('beforeRequest receives normalized options', async t => {
20+
await got(
21+
s.url,
22+
{
23+
json: true,
24+
hooks: {
25+
beforeRequest: [
26+
options => {
27+
t.is(options.path, '/');
28+
t.is(options.hostname, 'localhost');
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}
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]
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}
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}
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);
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});
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test('beforeRequest allows modifications', async t => {
37+
const res = await got(
38+
s.url,
39+
{
40+
json: true,
41+
hooks: {
42+
beforeRequest: [
43+
options => {
44+
options.headers.foo = 'bar';
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}
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]
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}
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}
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);
50+
t.is(res.body.foo, 'bar');
51+
});
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53+
test('beforeRequest awaits async function', async t => {
54+
const res = await got(
55+
s.url,
56+
{
57+
json: true,
58+
hooks: {
59+
beforeRequest: [
60+
async options => {
61+
await delay(100);
62+
options.headers.foo = 'bar';
63+
}
64+
]
65+
}
66+
}
67+
);
68+
t.is(res.body.foo, 'bar');
69+
});
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71+
test('beforeRequest rejects when beforeRequest throws', async t => {
72+
await t.throws(
73+
() => got(s.url, {
74+
hooks: {
75+
beforeRequest: [
76+
() => {
77+
throw new Error('oops');
78+
}
79+
]
80+
}
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}),
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{
83+
instanceOf: Error,
84+
message: 'oops'
85+
}
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);
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});
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89+
test('beforeRequest rejects when beforeRequest rejects', async t => {
90+
await t.throws(
91+
() => got(s.url, {
92+
hooks: {
93+
beforeRequest: [() => Promise.reject(new Error('oops'))]
94+
}
95+
}),
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{
97+
instanceOf: Error,
98+
message: 'oops'
99+
}
100+
);
101+
});
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test.after('cleanup', async () => {
104+
await s.close();
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});

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