azure-storage-js

One of the biggest change between latest Azure Storage JavaScript SDK V10 with legacy V2 is supporting Pipeline and Policies. In V10 SDK, you can create your own policy and inject it into the default pipeline, or create your own Pipeline.

A request policy is a filter triggered before and after a HTTP request. With a filter, we can do anything we what to HTTP requests and responses. For example, add a customized header, update URL or create logs. A HTTP pipeline is a group of policy factories.

Here we provide a sample to demonstrate how to customize the x-ms-client-request-id header for all outgoing HTTP requests.

Provide a valid service URL string with SAS token before execute the sample.
Following sample is in pure JavaScript.
Put classes into one file for demo purpose only.

const Azure = require("@azure/storage-blob");

// Create a policy factory with create() method provided
// In TypeScript, following factory class needs to implement Azure.RequestPolicyFactory type
class RequestIDPolicyFactory {
  // Constructor to accept parameters
  constructor(prefix) {
    this.prefix = prefix;
  }

  // create() method needs to create a new RequestIDPolicy object
  create(nextPolicy, options) {
    return new RequestIDPolicy(nextPolicy, options, this.prefix);
  }
}

// Create a policy by extending from Azure.BaseRequestPolicy
class RequestIDPolicy extends Azure.BaseRequestPolicy {
  constructor(nextPolicy, options, prefix) {
    super(nextPolicy, options);
    this.prefix = prefix;
  }

  // Customize HTTP requests and responses by overriding sendRequest
  // Parameter request is Azure.WebResource type
  async sendRequest(request) {
    // Customize client request ID header
    request.headers.set(
      "x-ms-client-request-id",
      `${this.prefix}_SOME_PATTERN_${new Date().getTime()}`
    );

    // response is Azure.HttpOperationResponse type
    const response = await this._nextPolicy.sendRequest(request);

    // Modify response here if needed

    return response;
  }
}

// Main function
async function main() {
  // Create a default pipeline with Azure.StorageURL.newPipeline
  const pipeline = Azure.StorageURL.newPipeline(
    new Azure.AnonymousCredential()
  );

  // Inject customized factory into default pipeline
  pipeline.factories.unshift(new RequestIDPolicyFactory("Prefix"));

  // Following URL needs include a valid SAS token
  let serviceURL = new Azure.ServiceURL(
    "https://account.blob.core.windows.net?sas",
    pipeline
  );

  const response = await serviceURL.listContainersSegment(
    Azure.Aborter.none,
    undefined
  );

  // Check customized client request ID
  console.log(response._response.request.headers.get("x-ms-client-request-id"));
}

main()
  .then(() => {
    "Successfully executed sample";
  })
  .catch(console.error);