Web API Conditional Operations Sample (Client-side JavaScript)

Artikel
11/28/2016

Applies To: Dynamics 365 (online), Dynamics 365 (on-premises), Dynamics CRM 2016, Dynamics CRM Online

This sample demonstrates how to perform conditional operations using Dynamics 365 Web API using client-side JavaScript.

Note

This sample implements the operations detailed in the Web API Conditional Operations Sample and uses the common client-side JavaScript constructs described in Web API Samples (Client-side JavaScript)

In this topic

Prerequisites
Run this sample
Code sample

Prerequisites

To run this sample, the following is required:

Access to Dynamics 365 online or on-premises version 8.0 or higher.
A user account with privileges to import solutions and perform CRUD operations, typically a system administrator or system customizer security role.

Run this sample

To run this sample, go to Microsoft CRM Web API Conditional Operations Sample (Client-side JavaScript) and download the Microsoft CRM Web API Conditional Operations Sample (Client-side JavaScript).zip sample file. Extract the contents and locate the WebAPIConditionalOperations_1_0_0_0_managed.zip managed solution. Import the managed solution into your Dynamics 365 organization and view the solution configuration page to run the sample. For instructions on how to import the sample solution, see Web API Samples (Client-side JavaScript).

Code sample

This sample includes two web resources:

WebAPIConditionalOperations.html
WebAPIConditionalOperations.js

WebAPIConditionalOperations.html

The WebAPIConditionalOperations.html web resource provides the context in which the JavaScript code will run.

<!DOCTYPE html>
<html>
<head>
 <title>Microsoft CRM Web API Conditional Operations Example</title>
 <meta charset="utf-8" />
 <script src="../ClientGlobalContext.js.aspx" type="text/javascript"></script>
 <script src="scripts/es6promise.js"></script>
 <script src="scripts/WebAPIConditionalOperations.js"></script>

 <style type="text/css">
  body {
   font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
  }
 </style>
</head>
<body>
 <h1>Microsoft CRM Web API  Conditional Operations Example</h1>
 <p>This page demonstrates the CRM Web API's Conditional Operations using JavaScript.</p>

 <h2>Instructions</h2>
 <p>
  Choose your preferences and run the JavaScript code.
  Use your browser's developer tools to view the output written to the console (e.g.: in IE11 or Edge, 
  press F12 to load the Developer Tools).
 </p>
 <form id="preferences">
  <p>This sample deletes the single record it creates.</p>
  <input type="button" name="start_samples" value="Start Sample" onclick="Sdk.startSample()" />
 </form>
</body>
</html>

WebAPIConditionalOperations.js

The WebAPIConditionalOperations.js web resource is the JavaScript library that defines the operations this sample performs.

"use strict";
var Sdk = window.Sdk || {};
/**
 * @function getClientUrl 
 * @description Get the client URL.
 * @return {string} The client URL.
 */
Sdk.getClientUrl = function () {
 var context;
 // GetGlobalContext defined by including reference to 
 // ClientGlobalContext.js.aspx in the HTML page.
 if (typeof GetGlobalContext != "undefined")
 { context = GetGlobalContext(); }
 else
 {
  if (typeof Xrm != "undefined") {
   // Xrm.Page.context defined within the Xrm.Page object model for form scripts.
   context = Xrm.Page.context;
  }
  else { throw new Error("Context is not available."); }
 }
 return context.getClientUrl();
}

// Global variables.
var clientUrl = Sdk.getClientUrl();     // e.g.: https://org.crm.dynamics.com
var webAPIPath = "/api/data/v8.1";      // Path to the web API.
var account1Uri;                        // e.g.: Contoso Ltd (sample)
var initialAcctETagVal;                 // The initial ETag value of the account created   
var updatedAcctETagVal;                 // The ETag value of the account after it is updated 

// Entity properties to select in a request.
var contactProperties = ["fullname", "jobtitle", "annualincome"];
var accountProperties = ["name"];
var taskProperties = ["subject", "description"];

/**
 * @function request
 * @description Generic helper function to handle basic XMLHttpRequest calls.
 * @param {string} action - The request action. String is case-sensitive.
 * @param {string} uri - An absolute or relative URI. Relative URI starts with a "/".
 * @param {object} data - An object representing an entity. Required for create and update actions.
 * @param {object} addHeader - An object with header and value properties to add to the request
 * @returns {Promise} - A Promise that returns either the request object or an error object.
 */
Sdk.request = function (action, uri, data, addHeader) {
 if (!RegExp(action, "g").test("POST PATCH PUT GET DELETE")) { // Expected action verbs.
  throw new Error("Sdk.request: action parameter must be one of the following: " +
      "POST, PATCH, PUT, GET, or DELETE.");
 }
 if (!typeof uri === "string") {
  throw new Error("Sdk.request: uri parameter must be a string.");
 }
 if ((RegExp(action, "g").test("POST PATCH PUT")) && (!data)) {
  throw new Error("Sdk.request: data parameter must not be null for operations that create or modify data.");
 }
 if (addHeader) {
  if (typeof addHeader.header != "string" || typeof addHeader.value != "string") {
   throw new Error("Sdk.request: addHeader parameter must have header and value properties that are strings.");
  }
 }

 // Construct a fully qualified URI if a relative URI is passed in.
 if (uri.charAt(0) === "/") {
  uri = clientUrl + webAPIPath + uri;
 }

 return new Promise(function (resolve, reject) {
  var request = new XMLHttpRequest();
  request.open(action, encodeURI(uri), true);
  request.setRequestHeader("OData-MaxVersion", "4.0");
  request.setRequestHeader("OData-Version", "4.0");
  request.setRequestHeader("Accept", "application/json");
  request.setRequestHeader("Content-Type", "application/json; charset=utf-8");
  if (addHeader) {
   request.setRequestHeader(addHeader.header, addHeader.value);
  }
  request.onreadystatechange = function () {
   if (this.readyState === 4) {
    request.onreadystatechange = null;
    switch (this.status) {
     case 200: // Success with content returned in response body.
     case 204: // Success with no content returned in response body.
     case 304: // Success with Not Modified.
      resolve(this);
      break;
     default: // All other statuses are error cases.
      var error;
      try {
       error = JSON.parse(request.response).error;
      } catch (e) {
       error = new Error("Unexpected Error");
      }
      reject(error);
      break;
    }
   }
  };
  request.send(JSON.stringify(data));
 });
};

/**
 * @function startSample
 * @description Runs the sample. 
 * This sample demonstrates conditional operations using CRM Web API. 
 * Results are sent to the debugger's console window.
 */
Sdk.startSample = function () {
 // Initializing...
 console.log("-- Sample started --");

 // Create the CRM account instance.
 var account = {
  name: "Contoso, Ltd",
  telephone1: "555-0000",// Phone number value will increment with each update attempt.
  revenue: 5000000,
  description: "Parent company of Contoso Pharmaceuticals, etc."
 };

 var uri = "/accounts"; // A relative URi to the account entity.
 Sdk.request("POST", uri, account) 
 .then( function (request) {
  console.log("Account entity created.");
  // Assign the Uri to the created account to a global variable.
  account1Uri = request.getResponseHeader("OData-EntityId");

  // Retrieve the created account entity.
  return Sdk.request("GET", account1Uri + "?$select=name,revenue,telephone1,description");
 })
 .then( function (request) {
  // Show the current entity properties.
  var account = JSON.parse(request.response);
  console.log(JSON.stringify(account, null, 2));

  initialAcctETagVal = account["@odata.etag"]; // Save the current ETag value.

  // Conditional Get START.
  // Attempt to retrieve using conditional GET with current ETag value.
  // Expecting nothing in the response because entity was not modified.
  console.log("-- Conditional GET section started --");
  var ifNoneMatchETag = { header: "If-None-Match", value: initialAcctETagVal };
  return Sdk.request("GET", account1Uri + "?$select=name,revenue,telephone1,description", null, ifNoneMatchETag);
 })
 .then( function (request) {
  console.log("Instance retrieved using ETag: %s", initialAcctETagVal);
  if (request.status == 304) {
   //Expected:
   console.log("\tEntity was not modified so nothing was returned.")
   console.log(request.response); //Nothing
  }
  else {
   //Not Expected:
   console.log(JSON.stringify(JSON.parse(request.response), null, 2));
  }

  // Modify the account instance by updating telephone1.
  // This request operation will also update the ETag value.
  return Sdk.request("PUT", account1Uri + "/telephone1", { value: "555-0001" })
 } )
 .then(  function (request) {
   console.log("Account telephone number updated.");

   // Re-attempt conditional GET with original ETag value.
   var ifNoneMatchETag = { header: "If-None-Match", value: initialAcctETagVal };
   return Sdk.request("GET", account1Uri + "?$select=name,revenue,telephone1,description", null, ifNoneMatchETag);
  }  )
  .then(  function (request) {
   if (request.status == 200) {
    // Expected.
    console.log("Instance retrieved using ETag: %s", initialAcctETagVal);
    var account = JSON.parse(request.response);
    updatedAcctETagVal = account["@odata.etag"]; //Capture updated ETag.
    console.log(JSON.stringify(account, null, 2));
   }
   else {
    // Not Expected.
    console.log("Unexpected status: %s", request.status)
   }
   // Conditional Get END.

   // Optimistic concurrency on delete and update START.
   console.log("-- Optimistic concurrency section started --");
   // Attempt to delete original account (only if matches original ETag value).
   var ifMatchETag = { header: "If-Match", value: initialAcctETagVal };
   return Sdk.request("DELETE", account1Uri, null, ifMatchETag);
  }  )
  .then( function (request) {
   // Success not expected.
   console.log("Unexpected status: %s", request.status)
  },
  // Catch error.
  function (error) {
   // DELETE: Precondition failed error expected.
   console.log("Expected Error: %s", error.message);
   console.log("\tAccount not deleted using ETag '%s', status code: '%s'.", initialAcctETagVal, 412)

   // Attempt to update account (if matches original ETag value).
   var accountUpdate = {
    telephone1: "555-0002",
    revenue: 6000000
   };
   var ifMatchETag = { header: "If-Match", value: initialAcctETagVal };
   return Sdk.request("PATCH", account1Uri, accountUpdate, ifMatchETag);
  })
  .then( function (request) {
   // Success not expected.
   console.log("Unexpected status: %s", request.status);
  },
  // Catch error.
  function (error) {
   // UPDATE: Precondition failed error expected.
   console.log("Expected Error: %s", error.message);
   console.log("\tAccount not updated using ETag '%s', status code: '%s'.", initialAcctETagVal, 412)

   // Re-attempt update if matches current ETag value.
   var accountUpdate = {
    telephone1: "555-0003",
    revenue: 6000000
   };
   var ifMatchETag = { header: "If-Match", value: updatedAcctETagVal };
   return Sdk.request("PATCH", account1Uri, accountUpdate, ifMatchETag);
  }  )
  .then( function (request) {
   if (request.status == 204) //No Content
   {
    // Expected.
    console.log("Account successfully updated using ETag '%s', status code: '%s'.",
     updatedAcctETagVal,
     request.status)
   }
   else {
    // Not Expected.
    console.log("Unexpected status: %s", request.status)
   }
   // Retrieve and output current account state.
   return Sdk.request("GET", account1Uri + "?$select=name,revenue,telephone1,description");
  }  )
  .then( function (request) {
   var account = JSON.parse(request.response);
   updatedAcctETagVal = account["@odata.etag"]; // Capture updated ETag.
   console.log(JSON.stringify(account, null, 2));
   // Optimistic concurrency on delete and update END.

   // Controlling upsert operations START.
   console.log("-- Controlling upsert operations section started --");

   // Attempt to insert (without update) some properties for this account.
   var accountUpsert = {
    telephone1: "555-0004",
    revenue: 7500000
   };
   var ifNoneMatchResource = { header: "If-None-Match", value: "*" };
   return Sdk.request("PATCH", account1Uri, accountUpsert, ifNoneMatchResource);
  }  )
  .then( function (request) {
   // Success not expected.
   console.log("Unexpected status: %s", request.status);
  },
  // Catch error.
  function (error) {
   // Precondition failed error expected.
   console.log("Expected Error: %s", error.message);
   console.log("\tAccount not updated using ETag '%s', status code: '%s'.", initialAcctETagVal, 412)

   // Attempt to perform same update without creation. 
   var accountUpsert = {
    telephone1: "555-0005",
    revenue: 7500000
   };
   // Perform operation only if matching resource exists. 
   var ifMatchResource = { header: "If-Match", value: "*" };
   return Sdk.request("PATCH", account1Uri, accountUpsert, ifMatchResource);
  } )
  .then( function (request) {
   if (request.status == 204)  // No Content.
   {
    // Expected.
    console.log("Account updated using If-Match '*'")
   }
   else {
    // Not Expected.
    console.log("Unexpected status: %s", request.status)
   }

   // Retrieve and output current account state.
   return Sdk.request("GET", account1Uri + "?$select=name,revenue,telephone1,description");
  })
  .then(  function (request) {
   var account = JSON.parse(request.response);
   updatedAcctETagVal = account["@odata.etag"]; // Capture updated ETag.
   console.log(JSON.stringify(account, null, 2));

   // Controlling upsert operations END.

   // Prevent update of deleted entity START.
   // Delete the account.
   return Sdk.request("DELETE", account1Uri);
  }
  )
  .then(
  function (request) {
   if (request.status == 204) {
    console.log("Account was deleted");

    // Attempt to update it.
    var accountUpsert = {
     telephone1: "555-0005",
     revenue: 7500000
    };
    // Perform operation only if matching resource exists. 
    var ifMatchResource = { header: "If-Match", value: "*" };
    return Sdk.request("PATCH", account1Uri, accountUpsert, ifMatchResource);
   }
  } )
  .then( function (request) {
   // Success not expected.
   // Without the If-Match header while using PATCH a new entity would have been created with the 
   // same ID as the deleted entity.
   console.log("Unexpected status: %s", request.status);

  },
  // Catch error.
  function (error) {
   // Not found error expected.
   console.log("Expected Error: %s", error.message);
   console.log("\tAccount not updated because it doesn't exist.");
  }

  )
 .catch(function (error) {
  console.log(error.message);
 });
}

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