then() functions to help us manage the response and data from our request. Because node-fetch is promise-based, we're chaining a couple of. The only parameter we've added to the fetch() function is the URL of the server we're making an HTTP request to.
![node-fetch download file node-fetch download file](https://twilio-cms-prod.s3.amazonaws.com/original_images/async-js-apis-nodejs.png)
NODE FETCH DOWNLOAD FILE CODE
In the code above, we're loading the node-fetch module and then fetching the Google home page. Let's make a simple GET request to Google's home page: fetch( '')
NODE FETCH DOWNLOAD FILE INSTALL
Next, install node-fetch as shown above and add an index.js file. This will create a package.json file in the directory. The node-fetch package allows you to do all of that.Ĭreate a directory for your project, cd into the directory and initialize a Node project with default settings: $ npm init -y You might want to retrieve text from the web server, a whole web page, or data from using REST API. There are two common use cases of fetching data from a web server. headers - an object containing response headers, a specific header can be accessed using the get() function.ok - equals true if status is a 2xx status code (a successful request).status and statusText - contain information about the HTTP status code.json() - parses the response body into a JSON object, and throws an error if the body can't be parsed.text() - returns the response body as a string.The function returns a Response object that contains useful functions and information about the HTTP response, such as: The optional options parameter is used when we want to use fetch() for anything other than a simple GET request, but we will talk about that more in-depth later. It has to be an absolute URL or the function will throw an error. The url parameter is simply the direct URL to the resource we wish to fetch. To install a specific version of the module, you can use npm: $ npm install Īs previously mentioned, the fetch() function in the node-fetch module behaves very similarly to the native window.fetch() function.
![node-fetch download file node-fetch download file](https://bezkoder.com/wp-content/uploads/2020/09/node-js-express-download-file-rest-api-example-list-response.png)
import from 'node:util' Ĭonst pipeline = promisify(stream.Note: The API between node-fetch 3.0 and 2.0 is the same, just the import differs. If you're requesting specific filename and extension, then you can just create a file with that name and extension and save the http response data to that file on your local drive.Īs for coding examples, the doc for node-fetch() shows examples of downloading data to a file using streams here. So, all you can do is make an http request for a specific resource (a url) and examine the http response to see if it returned data or returned some sort of http error such as a 404.Īs for filenames and extensions, that depends entirely upon whether you already know what to request and the server supports that being part of the URL or whether the server returns to you that information in an http header. You can't directly access a remote http server's file system. How do i check if the file exists on the server and if it does then download it on my machine with the same file name and extension? I'm not aware of any solution using a custom https agent. RateLimitMap() here: Let's you manage how many requests per second are sent.Ĭan this be solved using a custom https agent with node-fetch and setting the maxSockets to something like 10? MapConcurrent() here and pMap() here: These let you iterate an array, sending requests to a host, but manages things so that you only ever have N requests in flight at the same time where you decide what the value of N is. To control how many simultaneous requests are running at once, you can use any of these three options: It would be very helpful if someone could show a small example code how i would implement such functionality.
![node-fetch download file node-fetch download file](https://miro.medium.com/max/1400/1*CqEWBhVDOioRSIyCMwMkKA.png)
![node-fetch download file node-fetch download file](https://cheatcode-post-assets.s3.amazonaws.com/FYW1sfkC8CMagEM9/how-to-create-and-download-a-zip-file-with-node-js-and-javascript.png)
How do i limit the amount of concurrent requests to the server? Can this be solved using a custom https agent with node-fetch and setting the maxSockets to something like 10?.
NODE FETCH DOWNLOAD FILE HOW TO
how to limit the amount of concurrent requests to the server? how to save each file on the machine with same file name and extension? This is my code so far: const fetch = require('node-fetch') I tried using Promise.allSettled() but i also need a way to limit the amount of concurrent requests to the server otherwise i get rate-limited. Im using node-fetch but i don't exactly know how to implement this. So i need to download over 25'000 files from a server. I need help implementing a file downloader in nodejs.