feat: readme for cloud functions (#6914)

* feat: add token and nft injection

* feat: basic tests

* fix: get jest configured properly

* fix: change timeout

* fix: uninstall port ready

* fix: readd port ready

* fix: local tests work

* Update yarn.lock

* add lint disable for setup files

* fix: update dependencies

* fix: basic test suite for nfts/tokens

* feat: collection data

* fix: make tests more comprehensive

* fix: change matches to contains

* fix: tests for twitter alt image tag

* fix: image gen

* fix: add patch-package

* fix: update yarn install

* feat: basic image gen for nfts and collections

* fix: remove vibrant attempt

* use watermark asset

* dynamically grab color

* modularize code and prototype for token preview

* refactor code

* finalize css

* fix color grabber

* update tests

* fix up css

* refactor code a bit more

* remove console logs

* tests

* update tests

* update images based on design feedback

* network logos

* update lint

* slight refactoring

* more refactoring

* fix packages

* Update yarn.lock

* remove dynamically generated image stuff

* cleanup return values

* Create README.md

* Revert "Create README.md"

This reverts commit 7a91c98d384995fba914c9bf9a2fb3072793621f.

* Revert "Revert "Create README.md""

This reverts commit d0a4f5b95115e8ad47b6b3fd01b47806d68ad3d7.

* add docs for html rewriter

* Update README.md

* remove previously removed files

functions/README.md

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+# Cloudflare Cloud Functions
+
+## Purpose
+
+These functions utilize Cloudflare Functions to dynamically inject meta tags server side for richer link sharing capabilities.
+
+## Functions
+
+Currently, there are 2 types of cloudflare functions developed
+
+- Meta Data Injectors - Workers that inject [Open Graph](https://ogp.me/) standardized meta tags into the `header` of specific webpages.
+  - Currently we support this functionaltiy for three separate webpages: NFT Assets, NFT Collections, and Token Detail Pages
+  - These functions query data from GraphQL and then formats them into HTML `meta` tags to be injected
+- Dynamically Generated Images - Utilizes Vercel's [Open Graph Image Generation Library](https://vercel.com/docs/concepts/functions/edge-functions/og-image-generation) to create custom thumbnails for specific webpages
+  - Currently supports NFT Assets, NFT Collections, and Token Detail Pages
+  - These functions query data from GraphQL, and utilize `Satori` to convert HTML into a png image response which is then returned when the api is called.
+  - Can be found in the `api/image` folder. 
+
+## Testing
+
+Testing is done utilizing a custom jest environment as well as Cloudflare's local tester: `wrangler`. Wrangler enables testing locally by running a proxy to wrap `localhost`. Testing can be done the following ways.
+- Manually by running `yarn start:cloud` to setup wrangler on `localhost:3000`
+- Automated tests by running `yarn test:cloud` to setup both a jest and wrangler environment and automatically test features
+
+## Deployment
+
+Functions will be deployed to Cloudlfare where they will be ran automatically when the appropriate route is hit. 
+
+## Miscellaneous
+- Caching: In order to speed up webpage requests, repeated GraphQL queries will be saved and pulled using Cloudflare's Cache API.
+
+## Scripts
+
+- `yarn start:cloud` (NODE_OPTIONS=--dns-result-order=ipv4first PORT=3001 npx wrangler pages dev --node-compat --proxy=3001 --port=3000 -- yarn start), script to start local wrangler environment
+  - `npx wrangler pages dev`: this basis of this command which starts a local instance of wrangler to test cloud functions
+  - `--node-compat`: wrangler option that enables compatibility with Node.js modules
+  - `--proxy:3001`: telling the proxy to listen on port 3001
+  - `--port=3000`: telling wrangler to run our proxy on port 3000
+  - `NODE_OPTIONS=--dns-result-order=ipv4first`: wrangler still serves to IPv4 which isn't compatible with Node 18 which default resolves to IPv6 so we need to specify to serve to IPv4
+  - `PORT-3001 --yarn start`: runs default yarn start on port 3001
+- `yarn test:cloud` (NODE_OPTIONS=--experimental-vm-modules yarn jest functions  --watch --config=functions/jest.config.json), script to test cloud functions with jest
+  - `NODE_OPTIONS=--experimental-vm-modules`: support for ES Modules and Web Assembly
+  - `--config=functions/jest.config.json`: specifying which config file to use
+
+  ## Additional Documents
+  - [Open Graph Protocol](https://ogp.me/)
+  - [Open Graph Image Generation](https://vercel.com/docs/concepts/functions/edge-functions/og-image-generation)
+  - [Cloudflare Workers](https://developers.cloudflare.com/workers/)
+  - [HTML Rewriter](https://developers.cloudflare.com/workers/runtime-apis/html-rewriter/)
+  - [Cache API](https://developers.cloudflare.com/workers/runtime-apis/cache/)