Скачать или смотреть Resolving PDF Worker Issues with pdfjs-dist on Vercel Serverless Functions

Learn how to solve the "Cannot find module './pdf.worker.js'" error when using `pdfjs-dist` in Vercel Serverless Functions. Follow our guide for a seamless experience!
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Resolving PDF Worker Issues with pdfjs-dist on Vercel Serverless Functions

If you're working with PDFs in a Node.js environment on Vercel, you may run into a frustrating issue after deploying your application. Specifically, when using the pdfjs-dist package, you might see an error message that says:

[[See Video to Reveal this Text or Code Snippet]]

This problem arises due to differences between your local environment and the Vercel deployment environment. In this guide, we’ll walk you through the solution step-by-step so you can get your application up and running smoothly.

Understanding the Issue

When executing your code locally with the command vercel dev, everything seems to work fine. However, as soon as you deploy your application, the Vercel environment cannot locate the pdf.worker.js file, leading to the error.

Key Information

Local Node version: v16.16

Vercel Node version: 16.x

PDF.js Version: pdfjs-dist version 3.0.279

Step-by-Step Solution

Let’s dive into how to fix the issue by modifying your build process in Vercel.

Step 1: Modify Your Package Script

To start, you need to customize the compilation process specified in your package.json file. This involves adding a custom script for the build step.

[[See Video to Reveal this Text or Code Snippet]]

This line will ensure that Vercel runs your build.js script during the deployment process.

Step 2: Create the build.js File

Next, you need to create a build.js file that performs a specific modification on the pdf.js file in the pdfjs-dist package. This script will adjust the way the worker file is referenced.

Here's the content you should include in the build.js:

[[See Video to Reveal this Text or Code Snippet]]

Explanation of the Code

Read the Existing File: The script reads the current content of pdf.js.

Modify the File: It replaces the relative path to the pdf.worker.js with an absolute path using __dirname.

Rewrite the File: Finally, it writes this new content back to pdf.js.

Step 3: Redeploy Your Application

After implementing the changes, the last step is to redeploy your application on Vercel.

Commit your changes.

Push to your repository.

Trigger a redeployment.

Once completed, you should find that the error has been resolved, and your PDF handling capability is back in action!

Conclusion

Dealing with PDF files in serverless environments like Vercel can present unique challenges, particularly when using tools like pdfjs-dist. However, by following the steps outlined above, you can easily bypass the "Cannot find module './pdf.worker.js'" error.

If you encounter any further issues, feel free to comment below, and don’t forget to share this guide with anyone else facing similar hurdles!

Happy coding!