Repository: Azure/azure-functions-durable-js (ts)

Issue:
callHttp fails to make HTTP call
**Describe the bug**
`context.df.callHttp` doesn't work.

**Investigative information**

- Durable Functions extension version: 2.0.0
- durable-functions npm module version: 1.3.1
- Language (JavaScript/TypeScript) and version: JS
- Node.js version: 10.16.3

**To Reproduce**
Steps to reproduce the behavior:

1. Clone this repo: https://github.com/anthonychu/test-durable-js
1. ```bash
    npm i
    func extensions install
    cp local.settings.SAMPLE.json local.settings.json
    # Add storage connection string to local.settings.json
    func start
    ```
1. Call `http://localhost:7071/api/orchestrators/DurableFunctionsOrchestratorJS` to start the orchestrator that makes an http call.
1. Get the `statusQueryGetUri` in the response and use it to check the status. It should show an error:
    ```json
    {
        "name":"DurableFunctionsOrchestratorJS","instanceId":"d38d33aea86342c28a27b571def7e720",
        "runtimeStatus":"Failed",
        "input":null,
        "customStatus":null,
        "output":"Unexpected token while deserializing object: PropertyName. Path 'actions[0][0].actionType', line 12, position 21.",
        "createdTime":"2019-11-17T06:54:36Z",
        "lastUpdatedTime":"2019-11-17T06:54:37Z"
    }
    ```

@ConnorMcMahon @cgillum 

Pull request description:
Update DurableOrchestrationContext.callHttp signature
Fixes #119 

Patch:
diff --git a/src/durableorchestrationcontext.ts b/src/durableorchestrationcontext.ts
index 58a00ad..4fd1581 100644
--- a/src/durableorchestrationcontext.ts
+++ b/src/durableorchestrationcontext.ts
@@ -1,5 +1,5 @@
-import { DurableHttpRequest, DurableLock, EntityId, ITaskMethods, LockState,
-     RetryOptions, Task, TimerTask } from "./classes";
+import { EntityId, ITaskMethods, RetryOptions, Task, TimerTask } from "./classes";
+import { TokenSource } from "./tokensource";
 
 /**
  * Parameter data for orchestration bindings that can be used to schedule
@@ -130,7 +130,12 @@ export class DurableOrchestrationContext {
      *
      * @param req The durable HTTP request to schedule.
      */
-    public callHttp(req: DurableHttpRequest): Task {
+    public callHttp(
+            method: string,
+            uri: string,
+            content?: string | object,
+            headers?: { [key: string]: string },
+            tokenSource?: TokenSource): Task {
         throw new Error("This is a placeholder");
     }
 


Test patch:
diff --git a/test/testobjects/TestOrchestrations.ts b/test/testobjects/TestOrchestrations.ts
index d3cbffc..0b80a3e 100644
--- a/test/testobjects/TestOrchestrations.ts
+++ b/test/testobjects/TestOrchestrations.ts
@@ -1,4 +1,5 @@
 import * as df from "../../src";
+import { IOrchestrationFunctionContext } from "../../src/classes";
 
 export class TestOrchestrations {
     public static AnyAOrB: any = df.orchestrator(function*(context: any) {
@@ -182,7 +183,7 @@ export class TestOrchestrations {
         return output;
     });
 
-    public static SendHttpRequest: any = df.orchestrator(function*(context: any) {
+    public static SendHttpRequest: any = df.orchestrator(function*(context: IOrchestrationFunctionContext) {
         const input = context.df.getInput() as df.DurableHttpRequest;
         const output = yield context.df.callHttp(
             input.method,