How can I do Routing in Azure Functions?

We've shipped route support for HTTP Triggers in Azure Functions. You can now add a route property which follows ASP.NET Web API route naming syntax. (You can set it directly via the Function.json or via the portal UX)

"route": "node/products/{category:alpha}/{id:guid}"

Function.json:

{    "bindings": [        {            "type": "httpTrigger",            "name": "req",            "direction": "in",            "methods": [ "post", "put" ],            "route": "node/products/{category:alpha}/{id:guid}"        },        {            "type": "http",            "name": "$return",            "direction": "out"        },        {            "type": "blob",            "name": "product",            "direction": "out",            "path": "samples-output/{category}/{id}"        }    ]}

.NET sample:

public static Task<HttpResponseMessage> Run(HttpRequestMessage request, string category, int? id,                                                 TraceWriter log){    if (id == null)       return  req.CreateResponse(HttpStatusCode.OK, $"All {category} items were requested.");    else       return  req.CreateResponse(HttpStatusCode.OK, $"{category} item with id = {id} has been requested.");}

NodeJS sample:

module.exports = function (context, req) {    var category = context.bindingData.category;    var id = context.bindingData.id;    if (!id) {        context.res = {            // status: 200, /* Defaults to 200 */            body: "All " + category + " items were requested."        };    }    else {        context.res = {            // status: 200, /* Defaults to 200 */            body: category + " item with id = " + id + " was requested."        };    }    context.done();}

Official docs: https://docs.microsoft.com/en-us/azure/azure-functions/functions-bindings-http-webhook#url-to-trigger-the-function

Today, you'd have to use a service like Azure API Management to customize your routes.

There is a PR in progress to add custom routes to Azure Functions itself. The team is hoping it will land in the next release. https://github.com/Azure/azure-webjobs-sdk-script/pull/490

Note: I'm a PM on the Azure Functions team

azure-function-express

With azure-function-express you can use all expressjs functionalities including routing ;)

const createHandler = require("azure-function-express").createAzureFunctionHandler;const express = require("express");// Create express app as usualconst app = express();app.get("/api/:foo/:bar", (req, res) => {  res.json({    foo  : req.params.foo,    bar  : req.params.bar  });});// Binds the express app to an Azure Function handlermodule.exports = createHandler(app);

See more examples here including a way to handle all routes within a single Azure Function handler.

PS: Feel free to contribute to the project!