What is the correct way to promise-ify a request?

Question

What is the correct way to promise-ify a request?

The enchanting power of Bluebird promises meets the chaotic nature of request, a function masquerading as an object with methods.

In this straightforward scenario, I find myself with a request instance equipped with cookies via a cookie jar (bypassing request's global cookie handler). How can I seamlessly promisify it along with all its supported methods?

My ultimate goal is to:

invoke request(url) -> Promise
invoke request.getAsync(url) -> Promise
invoke request.postAsync(url, {}) -> Promise

It appears that Promise.promisifyAll(request) falls short (resulting in "postAsync is not defined").

javascript promise bluebird

Answer 1

Answer №1

Here is a solution that should do the trick:

var req = Promise.promisify(require("request"));
Promise.promisifyAll(req);

Keep in mind that by promisifying, req will no longer be a standalone function as promisification is done with prototype methods to handle the this context dynamically. This method is compatible with newer versions of bluebird and can be repeated when needed, especially for duplicating the request object for cookie use.

If you are working with Bluebird v3, remember to utilize the multiArgs option:

var req = Promise.promisify(require("request"), {multiArgs: true});
Promise.promisifyAll(req, {multiArgs: true})

This adjustment is necessary because the callback for request includes multiple arguments - (err, response, body): In Bluebird v3, only the first success value argument (i.e. response) is typically used, while the rest (i.e. body) is ignored if not specified otherwise.

Answer 2

Here is a solution that should do the trick:

var req = Promise.promisify(require("request"));
Promise.promisifyAll(req);

Keep in mind that by promisifying, req will no longer be a standalone function as promisification is done with prototype methods to handle the this context dynamically. This method is compatible with newer versions of bluebird and can be repeated when needed, especially for duplicating the request object for cookie use.

If you are working with Bluebird v3, remember to utilize the multiArgs option:

var req = Promise.promisify(require("request"), {multiArgs: true});
Promise.promisifyAll(req, {multiArgs: true})

This adjustment is necessary because the callback for request includes multiple arguments - (err, response, body): In Bluebird v3, only the first success value argument (i.e. response) is typically used, while the rest (i.e. body) is ignored if not specified otherwise.

Answer 3

Answer №2

If you're looking to make HTTP requests with ease, check out the request-promise module.

Say goodbye to old-fashioned promises and embrace the power of Bluebird with the Request module.

Simply install the module and start using request in promise style.

npm install request-promise

Answer 4

If you're looking to make HTTP requests with ease, check out the request-promise module.

Say goodbye to old-fashioned promises and embrace the power of Bluebird with the Request module.

Simply install the module and start using request in promise style.

npm install request-promise

Answer 5

Answer №3

It's worth noting that the third parameter in the callback, body, is unnecessary as it's already included in the response parameter. By examining the source code, you can observe that body serves as a shorthand for response.body, ensuring they are always synchronized.

Therefore, a straightforward promisification method, such as those outlined in other responses here, will suffice to access all response data.

const request = require('request')
const { promisify } = require('util')
const rp = promisify(request)

rp('https://example.com').then(({body, statusCode}) => ...)

This principle only applies to the response provided to the callback or promise. In contrast, the response object received during the response event is a standard http.IncomingMessage, devoid of a body property.

Answer 6

It's worth noting that the third parameter in the callback, body, is unnecessary as it's already included in the response parameter. By examining the source code, you can observe that body serves as a shorthand for response.body, ensuring they are always synchronized.

Therefore, a straightforward promisification method, such as those outlined in other responses here, will suffice to access all response data.

const request = require('request')
const { promisify } = require('util')
const rp = promisify(request)

rp('https://example.com').then(({body, statusCode}) => ...)

This principle only applies to the response provided to the callback or promise. In contrast, the response object received during the response event is a standard http.IncomingMessage, devoid of a body property.

Answer 7

Answer №4

Here is an illustrative example, utilizing util based on Node.js v11.10.0

import { get, post } from "request";
import { promisify } from "util";

const [getAsync, postAsync] = [get, post].map(promisify);


getAsync("http://stackoverflow.com")
    .then(({statusCode, body}) => { 
       //perform desired actions
     });

Alternatively, the same functionality can be achieved using async/await:

const foo = async () => {
    const {statusCode, body} = await getAsync("http://stackoverflow.com")
    // perform desired actions
}

Answer 8

Here is an illustrative example, utilizing util based on Node.js v11.10.0

import { get, post } from "request";
import { promisify } from "util";

const [getAsync, postAsync] = [get, post].map(promisify);


getAsync("http://stackoverflow.com")
    .then(({statusCode, body}) => { 
       //perform desired actions
     });

Alternatively, the same functionality can be achieved using async/await:

const foo = async () => {
    const {statusCode, body} = await getAsync("http://stackoverflow.com")
    // perform desired actions
}

What is the correct way to promise-ify a request?

Answer №1

Answer №2

Answer №3

Answer №4

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