DocByIdFromRoute.java

package com.danielrocks.function.cosmos.input;

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.CosmosDBInput;
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 retrieves a single document. 
 * The function is triggered by an HTTP request that uses route data to specify 
 * the ID to look up. 
 * That ID is used to retrieve a ToDoItem document from the specified database and collection.
 */

public class DocByIdFromRoute {

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

    @FunctionName("DocByIdFromRoute")
    public HttpResponseMessage run(
            @HttpTrigger(name = "req", 
              methods = {HttpMethod.GET, HttpMethod.POST}, 
              authLevel = AuthorizationLevel.ANONYMOUS,
              route = "todoitems/{id}")
            HttpRequestMessage<Optional<String>> request,        
            @CosmosDBInput(name = "database",
              databaseName = "ToDoList",
              collectionName = "Items",
              id = "{id}",
              partitionKey = "{id}",
              connectionStringSetting = "Cosmos_DB_Connection_String") 
            Optional<String> item,
            final ExecutionContext context) {
        
        // Item list
        context.getLogger().info("Parameters are: " + request.getQueryParameters());
        context.getLogger().info("String from the database is " + (item.isPresent() ? item.get() : null));

        // Convert and display
        if (!item.isPresent()) {
            return request.createResponseBuilder(HttpStatus.BAD_REQUEST)
                          .body("Document not found.")
                          .build();
        } 
        else {
            // return JSON from Cosmos. Alternatively, we can parse the JSON string 
            // and return an enriched JSON object.
            return request.createResponseBuilder(HttpStatus.OK)
                          .header("Content-Type", "application/json")
                          .body(item.get())
                          .build();
        }
    }
}