AI proxy spin app (#23)

- copied code from petersalomonsen/near-openai#11, which adds a [spin](https://github.com/fermyon/spin) app with a proxy to the OpenAI API, using the Fungible Token contract to cover usage cost
- hash `conversation_id` when calling the smart contract from the proxy to ensure that the smart contract does not reveal the conversation id that the AI proxy accepts
- added a test for the [aiconversation.js](https://github.com/petersalomonsen/quickjs-rust-near/blob/master/examples/fungibletoken/e2e/aiconversation.js) script that also shows the full process of starting a conversation and to get the refund when done

.github/workflows/test-aiproxy.yml

@@ -0,0 +1,34 @@
+name: "AI proxy tests"
+
+on:
+  push:
+    branches: [ master ]
+  pull_request:
+    branches: [ master ]
+
+jobs:
+  test:
+    name: "AI proxy"
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - name: Install dependencies
+        run: |
+          curl -fsSL https://developer.fermyon.com/downloads/install.sh | bash
+          sudo mv spin /usr/local/bin/
+          rustup target add wasm32-wasi
+          cargo install cargo-component --locked
+          spin plugin install -y -u https://github.com/fermyon/spin-test/releases/download/canary/spin-test.json
+      - name: Check formatting
+        working-directory: examples/aiproxy
+        run: |
+          (cd openai-proxy && cargo fmt --check)
+          (cd tests && cargo fmt --check)
+      - name: Build project
+        working-directory: examples/aiproxy
+        run: |
+          spin build
+      - name: Run tests
+        working-directory: examples/aiproxy
+        run: |
+          spin test

.vscode/settings.json

@@ -3,7 +3,9 @@
     "rust-analyzer.linkedProjects": [
         "examples/nft/Cargo.toml",
         "examples/minimumweb4/Cargo.toml",
-        "examples/purejs/Cargo.toml"
+        "examples/purejs/Cargo.toml",
+        "examples/aiproxy/openai-proxy/Cargo.toml",
+        "examples/aiproxy/tests/Cargo.toml"
     ]
 
 }

examples/aiproxy/.gitignore

@@ -0,0 +1 @@
+target

examples/aiproxy/README.md

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+# AI Proxy
+
+This folder contains a [Spin](https://www.fermyon.com/spin) application, based on the WASI 2 and the WebAssembly Component Model ( https://component-model.bytecodealliance.org/ ). It is implemented in Rust as a serverless proxy for the OpenAI API.
+
+There is a simple example of a web client in the [web](./web/) folder.
+
+The application will keep track of of token usage per conversation in the built-in key-value storage of Spin. The initial balance for a conversation is retrieved from the Fungible Token smart contract.
+
+To launch the application, make sure to have the Spin SDK installed. Set the environment variable `SPIN_VARIABLE_OPENAI_API_KEY` to your OpenAI API key.
+
+Then run the following commands:
+
+```
+spin build
+spin up
+```
+
+This will start the OpenAI proxy server at http://localhost:3000
+
+You can also launch the web client using for example [http-server](https://www.npmjs.com/package/http-server):
+
+```
+http-server web
+```
+
+You will then find the web client at http://localhost:8080. Here you can have a conversation with the AI model.