First, create a new file named download. Next, call the https. The second argument of the method will be the callback function you want to run once a response stream has been received:. For example, I want to save the image and name it as downloaded-image.
Now you need to create a new writable stream using fs. The fs module will create the writable stream on the current folder by default:. Since the HTTP. One each data event, write the data to the writeable stream. Once the server finishes sending data, close the instance of fs. If you use fs. Use fs. To download files using curl in Node. We are using spawn instead of exec for the sake of convenience - spawn returns a stream with data event and doesn't have buffer size issue unlike exec.
That doesn't mean exec is inferior to spawn ; in fact we will use exec to download files using wget. Show 3 more comments. MikeL 5, 38 38 silver badges 41 41 bronze badges. Augusto Roman Augusto Roman 6 6 silver badges 4 4 bronze badges.
What for are you storing request into a variable? You are right, there is no need to save the request, its not used anyway.
That's what you mean? Yes, I think that's what polkovnikov. Per default the fs. Bjarke Pjedsted Bjarke Pjedsted 4 4 silver badges 8 8 bronze badges. Two comments on this: 1 it should probably reject Error objects, not strings, 2 fs. This works great! No errors popped up but the.
Removing the logic for the flag fixed it. Just wanted to point that out if someone had the issues with the approach. Is there a memory leak in this answer: stackoverflow. You can add timeout like I did in http. The memory leak is only if the file take too long to be downloaded. Based on the other answers above and some subtle issues, here is my attempt.
Check the file does not exist before hitting the network by using fs. Only create the fs. This reduces the amount of fs. Even on a OK we can still possibly reject due to an EEXIST file already exists imagine another process created the file whilst we were doing network calls.
Recursively call download if you get a Moved Permanently or Found Moved Temporarily redirect following the link location provided in the header. The issue with some of the other answers recursively calling download was that they called resolve download instead of download This way the nested chain of promises resolve in the correct order. It might seem cool to clean up the temp file asynchronously, but I chose to reject only after that completed too so I know that everything start to finish is done when this promise resolves or rejects.
Josh Peak Josh Peak 4, 4 4 gold badges 33 33 silver badges 48 48 bronze badges. You shouldn't waste resources doing the download if the destination file already exists.
Do the check first if possible. Phil Really good point. I have updated the example with an earlier guard check before falling into the recursive networking calls but left the success file handling code the same. This short circuit guard statement should save some time in this case now. JoshPeak what if the file is updated on server. This solution is only checking the name of the resource.
If the file is different on the server then comparing modifed timestamps and hashes of content would be required conditions to invalidate the local cache. Correct cache invalidation is beyond the scope of this question and warrants it's own question and depends how servers implement HTTP ETag protocols.
Vince Yuan's code is great but it seems to be something wrong. But we don't check the result if callback callback err. Feel Physics Feel Physics 2, 4 4 gold badges 23 23 silver badges 36 36 bronze badges.
I prefer request because you can use both http and https with it. Looks like Request has been deprecated github. No new changes are expected to land. You can either use the built-in modules like fs and https or 3rd party open-source libraries.
The file could be anything: a PDF file, an image, or a simple text file. The fs module grants you access to the filesystem to read and write files in Node. You can also use the download package from the NPM registry if you do not like low-level Node.
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