Sending custom headers for each file

[danimt]

Is it possible to send custom headers for each file?

I currently see the option to add extra headers to the global flow object, but that will impact all uploads. In my app I need to send the values pertinent to each uploading file.

Thanks,
Daniel

[AidasK]

No, we will need to edit flow.js a bit.
https://github.com/flowjs/flow.js/blob/master/src/flow.js#L1380
Feel free to make a pull request, I think this should be fixed the same way as query parameter: https://github.com/flowjs/flow.js/blob/master/src/flow.js#L1351

[danimt]

Thank you for your quick response. I'll send a PR as soon as I can work on this. 👍

[danimt]

I just had time and I realised I don't need to modify the current behaviour.

I can just add the new query parameters by accessing the flowFile.

flowFile.flowObj.opts.query['parameterName'] = 'parameterValue'

Is this the safest way for adding headers?

[AidasK]

flowFile.flowObj.opts.query['parameterName'] = 'parameterValue'
In this way, you are changing query parameters for all requests, this is the same as:
flow.opts.query['parameterName'] = 'parameterValue'
or

var flow = new Flow({
  query:{parameterName:'parameterValue'}
});

Although, i suggest using query as a function:

var flow = new Flow({
  query: function (flowFile, flowChunk) {
    // this will be called before every request
    // make some logic with flowFile to add some proper values.
    return {parameterName:'parameterValue'}
  }
});

But this is not supported for headers, a pull request would be needed.

[danimt]

The way I see it, we could have it either by assigning the parameters to the flowFile, without any control per-chunk, or the query function that would allow for different parameters per-chunk.

Both would be nice, as in some cases I would like to assign the same parameters for all chunks, or change parameters for each chunk.

[AidasK]

This is the way to assign parameters per file:

var flow = new Flow({
  query: function (flowFile, flowChunk) {
    if (flowFile.myparams) {
       return flowFile.myparams;
    } 
    // generate some values
    flowFile.myparams = {parameterName:'parameterValue'};
    return flowFile.myparams;
  }
});

Hope this solves your problem.

[danimt]

Thank you. This works perfectly ;) 👍

This should be documented somewhere to help other users.

[AidasK]

Added support for custom headers. 67f70d6