Monday, 17 February 2014

Consuming ASP.NET Web API OData Batch Update From JavaScript

Consuming OData with plain JavaScript is a bit painful, as we would require handling some of the low-level conversions. datajs is a JavaScript library that simplifies this task.

datajs converts data of any format that it receives from the server to an easily readable format. The batch request sent is a POST request to the path /odata/$batch, which is made available if batch update option is enabled in the OData route configuration.

As seen in the last post, a batch update request bundles of a number of create put and patch requests. These operations have to be specified in an object literal. Following snippet demonstrates it with a create, an update and a patch request:

var requestData = {
    __batchRequests: [{
        __changeRequests: [
                requestUri: "/odata/Customers(1)",
                method: "PATCH",
                data: {
                    Name: "S Ravi Kiran"
                requestUri: "/odata/Customers(2)"
                data: {
                    Name: "Alex Moore",
                    Department: "Marketing",
                requestUri: "/odata/Customers",
                method: "POST",
                data: {
                    Name: "Henry",
                    Department: "IT",
                    City: "Las Vegas"

Following snippet posts the above data to the /odata/$batch endpoint and then extracts the status of response of each request:

    requestUri: "/odata/$batch",
    method: "POST",
    data: requestData,
    headers: { "Accept": "application/atom+xml"}
}, function (data) {
    for (var i = 0; i < data.__batchResponses.length; i++) {
        var batchResponse = data.__batchResponses[i];
        for (var j = 0; j < batchResponse.__changeResponses.length; j++) {
            var changeResponse = batchResponse.__changeResponses[j];
}, function (error) {
}, OData.batchHandler);

Happy coding!

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