TriggerStringGet.java

package com.danielrocks.function.http.trigger;

import java.util.Optional;

import com.microsoft.azure.functions.ExecutionContext;
import com.microsoft.azure.functions.HttpMethod;
import com.microsoft.azure.functions.HttpRequestMessage;
import com.microsoft.azure.functions.HttpResponseMessage;
import com.microsoft.azure.functions.HttpStatus;
import com.microsoft.azure.functions.annotation.AuthorizationLevel;
import com.microsoft.azure.functions.annotation.FunctionName;
import com.microsoft.azure.functions.annotation.HttpTrigger;

/**
 * Azure Functions with HTTP Trigger.
 * 
 * The following example shows a Java function that reads a parameter from:
 * 
 * 1) The query string, for GET requests;
 * 
 * as a String and returns a JSON document.
 * 
 */

public class TriggerStringGet {

    /**
     * This function listens at endpoint "/api/TriggerStringGet". Invoke it using "curl" command in bash:
     * 1. curl {your host}/api/TriggerStringGet?id={some_id}
     */

    @FunctionName("TriggerStringGet")
    public HttpResponseMessage run(
            @HttpTrigger(name = "req", 
              methods = {HttpMethod.GET}, 
              authLevel = AuthorizationLevel.ANONYMOUS)
            HttpRequestMessage<Optional<String>> request,
            final ExecutionContext context) {
        
        // Item list
        context.getLogger().info("GET parameters are: " + request.getQueryParameters());

        // Get named parameter
        String id = request.getQueryParameters().getOrDefault("id", "");

        // Convert and display
        if (id.isEmpty()) {
            return request.createResponseBuilder(HttpStatus.BAD_REQUEST)
                          .body("Document not found.")
                          .build();
        } 
        else {
            // return JSON from to the client
            // Generate document
            final String name = "fake_name";
            final String jsonDocument = "{\"id\":\"" + id + "\", " + 
                                         "\"description\": \"" + name + "\"}";
            return request.createResponseBuilder(HttpStatus.OK)
                          .header("Content-Type", "application/json")
                          .body(jsonDocument)
                          .build();
        }
    }
}