Sometimes you might need to generate a PDF. And me being me, I'd like 100% of those times for PDF generation to be through a serverless function. This repo should help you set up a Node-based serverless function (Azure Functions) which runs pdf-lib and stores your custom fonts and your created documents on Azure Blob Storage. A time-scoped, secure URL is posted back when the PDF has been generated.

Why pdf-lib and not [insert any other library]?. Well, because some of the big ones just don't work other than through anecdotal Stack Overflow evidence. Having spent many, many more hours than I wish I'd ever spent getting them working, I turned to pdf-lib because it accepts Webpack, our overall stack, and has a good API. Pedigree and years of service mean nothing if your library won't build (or breaks) with modern tools. Keep that in mind, kids!

To do this you'll need to:

1. Deploy some storage to contain your custom fonts (Roboto included for demo purposes)
2. Upload custom fonts
3. Configure your function to use your new STORAGE_ACCOUNT_KEY and AZURE_STORAGE_CONNECTION_STRING
4. Deploy the function

Stack

• Serverless Framework
• Azure Functions + Azure Storage (for storing the functions, fonts and documents)
• Webpack for bundling and optimizing
• Babel for transpiling files
• Typescript so we can write better code

• Azure account
• Logged in to Azure through environment
• High enough credentials to create new function and storage resources
• Serverless Framework installed on your system

Install dependencies with npm install or yarn add.

Located at src/config.ts.

You will need to provide STORAGE_ACCOUNT_KEY and AZURE_STORAGE_CONNECTION_STRING for your Azure Storage.

1. az account clear
2. az login

Then set credentials as per instructions at https://github.com/serverless/serverless-azure-functions#advanced-authentication.

Run sls offline. After a bit of building files and doing its magic, you get a prompt looking like:

Http Functions:

generatePdf: [POST] http://localhost:7071/generatePdf

Hit that URL and you're ready! It doesn't do auto-reloads though.

NOTE! Your Node version will need to be 12 (or whatever version is used on Azure). One way of handling multiple Node versions is with nvm. If you are set on using it, these instructions should get you up and ready for development:

1. nvm install 12, to install Node 12
2. nvm use 12, to use Node 12
3. When you are done, run nvm unload but this will also eject the environment variables so nvm will be an unknown command from that point on (just run the commands again from ~/.zshrc or where ever those got put in the first place)

The only available endpoint. All three fields (user, presentation, email) are mandatory. Change these and add/remove as you need.

You can generate a single PDF at a time.

/POST http://localhost:7071/generatePdf

{
  "user": "Some User",
  "presentation": "Made a ton of GitHub repos",
  "email": "[email protected]"
}

https://azuregeneratepdfdemo.blob.core.windows.net/azuregeneratepdfstorage/documents/59f7b2dd-5ca7-4afb-929a-81e69f7179e5.pdf?sv=2019-12-12&st=2020-07-16T22%3A11%3A39Z&se=2020-07-16T22%3A31%3A39Z&sr=b&sp=racwd&sig=RVgjpCx9PzB1sMY9eMCPp91uuhvmMZ5PmSL%2FKqqSgbU%3D

Run npm run deploy:storage or yarn deploy:storage.

Always check the values/exports in shell scripts before running them!

Run npm run upload:fonts or yarn run deploy:fonts. This will upload the fonts/ folder to the new storage.

Run npm run deploy or yarn deploy or sls deploy.

Make sure you've put your STORAGE_ACCOUNT_KEY and AZURE_STORAGE_CONNECTION_STRING in src/config.ts!

Run npm run teardown or yarn run teardown. This command does the following:

• Runs sls remove to remove the function stack.
• Runs sh ./scripts/teardown.sh to remove the storage for fonts and documents.

• https://docs.microsoft.com/en-us/azure/storage/blobs/storage-quickstart-blobs-nodejs

• It's not uncommon to get a 400 error (Error creating APIM Property) when deploying with sls deploy. Just wait a few seconds and try again, and it should normally work on the second attempt.
• You cannot set currently (July 2020) set timeout, memory size, or OS type for functions through serverless.yml.
• There is supposedly support to configure apim (API Management) in serverless.yml but somehow you will start getting deployment errors (-> Function App not ready. Retry 0 of 30... and continuing) if you mess about with that stuff. To the best of my abilities, I think I've located the error to be on the backends section. Maybe it's not mapping correctly? Following a slightly modified version of the config in the Serverless Framework provider reference does not work, at least.
• Serverless Framework and Azure together seem to have—at best—a fragile friendship. Expect that deployments stop working every now and then. Resolution is unclear; removing and redeploying (while a useless option that cannot be done safely in production) does not always seem to work either. Moving the region (also unsafe) seems to work better, but only ever do that during development and not after.