Upload files through http

I've just spent an hour of trying to figure out why my uploader doesn't work because it's quite hard to notice that there are actually only 4 dashes in the first boundary string but 6 dashes in the other boundary strings. In other words: When using the boundary string to separate the individual form data, it has to be prefixed by two dashes: -- It's described in RFC of course but I think it should be pointed out here as well — Andreas.

Show 5 more comments. This is "not reliably interpretable by computer", so it should never be used in production, and we will not look further into it. How to generate the examples Once you see an example of each method, it becomes obvious how they work, and when you should use each one.

Create files to upload: echo 'Content of a. Tested on: Ubuntu RFC clearly mentions that those two leading dashes -- are required: 4. So this cannot be used for files.

Comparison File uploads often contain lots of non-printable characters e. How would you add a binary attachment? I don't know which heuristics it uses, but most likely the file extension is amongst them. This may answer the question: stackoverflow. But please remove the irrelevant content from your profile. It is against the spirit of SO. About username: to me, the spirit of SO is that everyone should have the best information at all times.

KumarHarsh not enough detail to answer I think. Please open a new super detailed questions. Show 9 more comments. Wilt Wilt How do you configure a server side service for this with Asp.

Net 4. Will it handle multiple input parameters as well, such as userId, path, captionText etc? AsleG Nope, it is only for sending a single file as the content of your request. I am not an Asp. Net expert, but you should simply pull the content a blob out of the request and save it to a file using the Content-Type from the header. AsleG Maybe this link can help — Wilt. These 'weird strings' you refer to are the form boundaries normally used for separating the form data into parts on the server.

Show 6 more comments. I have this sample Java Code: import java. Koray Tugay Koray Tugay The Overflow Blog. Podcast Making Agile work for data science. Stack Gives Back Featured on Meta.

New post summary designs on greatest hits now, everywhere else eventually. This post may contain affiliate links which generate earnings for Techcoil when you make a purchase after clicking on them.

Such earnings keep Techcoil running at no added cost to your purchases. Please read my disclosure for more info. Undeniably, the HTTP protocol had become the dominant communication protocol between computers. If you are building that client with Python 3, then you can use the requests library to construct the HTTP multipart request easily.

In case you need it, this is how we can upload a file and some data through HTTP multipart in Python 3 using the requests library. Assume that we are building a Python 3 application for your Raspberry Pi 3. Whenever a button is pressed, an image will be captured with the camera on your Raspberry Pi along with temperature read from a DHT11 sensor.

While still being on the loop:. If status is true, we append the data variable to the body which represents the HTTP body. Now that we created methods which build the HTTP body by appending any post data and file data, we must create one more which will close the body. For one more time here the body parameter is marked as inout , so the data argument will be passed by reference and the changes made to it inside this method will become visible to the caller too.

Besides that, notice the line breaks before and after the closing string which ensure that the closing boundary will be the only content in the line. Here is its definition:. In accordance to what we did to the other two existing public methods, we are going to perform all actions in this method asynchronously.

In code that means:. With userInitiated value in the quality of service parameter we give our task a relatively high priority in execution. Note that we mark self as weak in the closure since the RestManager instance used to perform the file uploading can potentially become nil, and that practically means that self is from now on an optional. This introduces a couple of new needs as you will see next.

Notice that since self is used as an optional, boundary becomes an optional value too, regardless of the fact that createBoundary does not return an optional. Once again, since self is an optional, body might be nil in case self is nil. So, in that case we call the completion handler with another custom error and we return from the method.

Time to add the files to be uploaded to the HTTP body. The method we use here is already implemented in the RestManager class and we discussed about it in the previous tutorial.

There is one last thing to do before we test out everything. To add the two new custom errors to the CustomError enum. Find it in the RestManager class and update it as shown next:. The time to test file uploading has finally come. Switch to the ViewController. For starters, we are going to upload a single file only, and here we will prepare the FileInfo object that will contain its data.

See that we are using the custom initializer we created in the FileInfo structure here. Of course, we also print the list of failed to be uploaded files in case there is any. If you followed everything step by step up until here, you should get this in Xcode:.

I wanted to make the small demo server and the file uploading process behave as much naturally as possible, so files sent to this server implementation are actually… being uploaded! The uploaded file is there which proves that file uploading is actually working! Right after the initialization of the FileInfo object in the uploadSingleFile method add the following two lines:. Here it is:.

At the end we call again the upload files:toURL: method which will trigger the actual upload request. Note that the current server implementation supports up to 10 simultaneous files to be uploaded. Of course you are free to change that limit according to your preference. Starting in the previous tutorial where we created the first version of the RestManager class and continuing in this one where we added the file uploading feature, we have managed to build a small and lightweight class capable of covering our needs in making web requests.

I hope what I shared with you here today to be of some value, and I wish you are enjoying RESTful services even more now. You are always welcome to add more features or adapt the current implementation according to your needs. See you next time! For reference, you can download the full project on GitHub.

Using Swift of course! Data contentsOf: url self. Data contentsOf : url. UInt8 ascii: "z". UInt8 ascii : "z". UInt8 ascii: "9". UInt8 ascii : "Z". UInt8 ascii : "9". FileInfo fileInfo. Data contentsOf : fileURL.