Azure-functions-host: Simplify Node Http Response Logic

[mamaso]

Currently a http response exists in two forms:

1. context.res = bodyValue; // res is interpreted as 200 with body bodyValue
2. context.res = { body: bodyValue, headers: ..., status: ... } // res is fully specified object

Removing option 1 is something we ought to consider, as it has some negatives:

• We are forced to guess whether the returned object is a response based on existence of 'body' property, which in a couple cases is incorrect:
  
  
  
  • bodyValue has a body property (workaround is nested body inside body)
  
  
  • a response object is returned with only headers and status
  
  
• The 'magic' code of 1 doesn't save lines of code
  
  
  
  • context.res = bodyValue; context.done(); vs context.res.send(bodyValue);
  
  
• We would decrease the matrix of things we need to test (currently, different behavior in content type handling between 1 and 2)
• Simplified documentation and examples with a single recommended way of interacting with http in node

978 #814

[johnnliu]

figured this one out. 1.0 don't like raw body content. can't validate webhook that wanted text/plain response. argh.

[fabiocav]

@johnnliu for full control of the response (send raw payload, manage content type, etc), we've added a flag you can set.
Details are available here: https://github.com/Azure/azure-webjobs-sdk-script/issues/965#issuecomment-262618266

[giuleon]

@fabiocav I tried this snippet to validate the SharePoint List web hook:
context.res = {
status: 200,
body: req.query.validationtoken,
headers: {
'Content-Type': 'text/plain'
},
isRaw: true
}
In req.query.validationtoken there is the sharepoint token for the validation that the function must to send back to SharePoint like a response in text plain, but I receive ever the message "Failed to validate the notification URL" in fact with postman if I call my function there is no response and the content type is not available

[giuleon]

No news about this issue ?

[mathewc]

Can you share the rest of your code? I just tried myself and this works fine - I get the code back with the correct content type. Your issue is likely that your output binding for the response is using $return but in your context.done() you're not returning the response there. If you want to set the response via context.res then change your http output binding name to res.

module.exports = function (context, req) {
    context.res = {
        status: 200,
        body: req.query.validationtoken,
        headers: {
            'Content-Type': 'text/plain'
        },
        isRaw: true
    };
    context.done();
};

[giuleon]

Only for testing I created this function:

`module.exports = function (context, req) {
context.log('Node.js HTTP trigger function processed a request. RequestUri=%s', req.originalUrl);

if (req) {
    if (req.query && req.query.validationtoken) {
        // if validationtoken is specified in query
        // immediately return token as text/plain
        context.log(req.query);
        context.log(req.query.validationtoken);

        context.res = {
                    status: 200,
                    body: req.query.validationtoken,
                    headers: {
                        'Content-Type': 'text/plain'
                    },
                    isRaw: true
                };
    }
}
context.done();

};`

I'm using postman to send a post to my azure function with in query string validationtoken=123456778 as I expect from SharePoint but doesn't work for me:

[mathewc]

As I mentioned above, I think the issue is your function.json and how your response is bound. Here's what mine looks like. Note that my output is res not $return. What does yours look like?

{
  "bindings": [
    {
      "authLevel": "function",
      "type": "httpTrigger",
      "direction": "in",
      "name": "req"
    },
    {
      "type": "http",
      "direction": "out",
      "name": "res"
    }
  ]
}

[giuleon]

Thank you @mathewc the bindings was wrong "$return" ;-)

[ghost]

Maybe slightly OT but is there a specific reason you didn't just pass in the standard IncomingMessage and ServerResponse objects from node but rolled your own req and res types?

[mamaso]

@stefan-akelius At present all function triggers are routed through a C# process. We use edgejs for interop between node and C#. The requests are served in C# so unfortunately we don't have access to a node generated IncomingMessage or ServerResponse (I'd love to support those types natively as well).

[yvele]

@stefan-akelius You might have a look at azure-function-express (we needs contributors)