{"id": "1625485c-b5f8-4dee-a884-b9ce8d4c66da", "conversation": "Fetch and Save JSON\n3e305f5c-4683-42fb-bd9c-11100b08ad64", "author_role": "user", "content": "Write a new JavaScript fetch() function which calls the old one but also saves the JSON that is retrieved - if it is used to retrieve JSON - in a window.fetchedData object", "create_time": "2023-03-26 01:44:42"}
{"id": "89955ec0-b6bf-48dc-bbf5-9af498a84bce", "conversation": "Fetch and Save JSON\n3e305f5c-4683-42fb-bd9c-11100b08ad64", "author_role": "assistant", "content": "To achieve this, you can create a new function called `fetchAndSaveJson` that wraps the native `fetch` function. This new function will call the original `fetch` function, and if the response contains JSON data, it will save the JSON data to a `window.fetchedData` object. Here's how you can implement this:\n\n```js\n// Define a global object to store fetched JSON data\nwindow.fetchedData = {};\n\n// Define a new fetch function that wraps the native fetch\nasync function fetchAndSaveJson(url, options) {\n  try {\n    // Call the native fetch function\n    const response = await fetch(url, options);\n\n    // Check if the response has a JSON content type\n    const contentType = response.headers.get('content-type');\n    if (contentType && contentType.includes('application/json')) {\n      // If the response is JSON, parse it and save it to the fetchedData object\n      const jsonData = await response.json();\n      window.fetchedData[url] = jsonData;\n      return jsonData;\n    }\n\n    // If the response is not JSON, return the original response\n    return response;\n  } catch (error) {\n    // Handle any errors that occur during the fetch\n    console.error('Error fetching and saving JSON:', error);\n    throw error;\n  }\n}\n\n// Example usage\nfetchAndSaveJson('https://jsonplaceholder.typicode.com/todos/1')\n  .then(data => {\n    console.log('Fetched JSON data:', data);\n    console.log('Data saved in window.fetchedData:', window.fetchedData);\n  })\n  .catch(error => {\n    console.error('Error:', error);\n  });\n```\n\nIn this implementation, the `fetchAndSaveJson` function takes the same arguments as the native `fetch` function (`url` and `options`). It then calls the native `fetch` function with these arguments and checks the `content-type` header of the response to determine if the response contains JSON data. If the response is JSON, the function parses the JSON data, saves it to the `window.fetchedData` object using the URL as the key, and returns the parsed JSON data. If the response is not JSON, the function returns the original response.\n\nNote that this implementation assumes that the `window.fetchedData` object is used exclusively for storing fetched JSON data, and that the URLs used to fetch data are unique. If there are multiple requests to the same URL, the data from the latest request will overwrite the data from previous requests.", "create_time": "2023-03-26 01:45:02"}
{"id": "bd4bdca2-b608-41a5-8f26-7fdac768a9a7", "conversation": "Fetch and Save JSON\n3e305f5c-4683-42fb-bd9c-11100b08ad64", "author_role": "user", "content": "No I need to replace the old window.fetch() function entirely - I want to patch it so that I can intercept calls made by other existing code", "create_time": "2023-03-26 01:45:14"}
{"id": "e18e0cc1-cec1-43cb-9ef0-9ec97820333d", "conversation": "Fetch and Save JSON\n3e305f5c-4683-42fb-bd9c-11100b08ad64", "author_role": "assistant", "content": "To replace the native `window.fetch` function and intercept calls made by other existing code, you can create a new function that wraps the original `fetch` function. You can then assign this new function to `window.fetch`, effectively \"patching\" the native `fetch` function. Here's how you can do this:\n\n```js\n// Define a global object to store fetched JSON data\nwindow.fetchedData = {};\n\n// Store a reference to the original fetch function\nconst originalFetch = window.fetch;\n\n// Define a new fetch function that wraps the original fetch\nwindow.fetch = async function(url, options) {\n  try {\n    // Call the original fetch function\n    const response = await originalFetch(url, options);\n\n    // Check if the response has a JSON content type\n    const contentType = response.headers.get('content-type');\n    if (contentType && contentType.includes('application/json')) {\n      // If the response is JSON, clone the response so we can read it twice\n      const responseClone = response.clone();\n      // Parse the JSON data and save it to the fetchedData object\n      const jsonData = await responseClone.json();\n      window.fetchedData[url] = jsonData;\n    }\n\n    // Return the original response\n    return response;\n  } catch (error) {\n    // Handle any errors that occur during the fetch\n    console.error('Error fetching and saving JSON:', error);\n    throw error;\n  }\n};\n\n// Example usage\nfetch('https://jsonplaceholder.typicode.com/todos/1')\n  .then(response => response.json())\n  .then(data => {\n    console.log('Fetched JSON data:', data);\n    console.log('Data saved in window.fetchedData:', window.fetchedData);\n  })\n  .catch(error => {\n    console.error('Error:', error);\n  });\n```\n\nIn this implementation, we store a reference to the original `fetch` function in the `originalFetch` variable. We then define a new function that calls `originalFetch` with the provided arguments, checks the `content-type` header of the response to determine if the response contains JSON data, and saves the JSON data to the `window.fetchedData` object using the URL as the key. Finally, we assign this new function to `window.fetch`, effectively replacing the native `fetch` function.\n\nNote that we use `response.clone()` to create a clone of the response before reading the JSON data. This is necessary because the response body can only be read once, and we want to allow the caller to read the response body as well.\n\nThis implementation assumes that the `window.fetchedData` object is used exclusively for storing fetched JSON data, and that the URLs used to fetch data are unique. If there are multiple requests to the same URL, the data from the latest request will overwrite the data from previous requests.", "create_time": "2023-03-26 01:45:33"}
{"id": "534a10c5-b320-4b12-a2c2-a56eb1c84dfd", "conversation": "Starlette CORS Forwarding App\n08a446e2-51a2-4abe-89ed-64b7887e12a0", "author_role": "system", "content": "You are ChatGPT, a large language model trained by OpenAI.\nKnowledge cutoff: 2021-09\nCurrent date: 2023-03-25", "create_time": "2023-03-26 04:10:49"}
{"id": "395b6bcd-d87d-4dda-9879-51200da31272", "conversation": "Starlette CORS Forwarding App\n08a446e2-51a2-4abe-89ed-64b7887e12a0", "author_role": "user", "content": "Write a web app in python Starlette which has CORS enabled - including for the auth header - and forwards all incoming requests to any path to another server host specified in an environment variable ", "create_time": "2023-03-26 04:10:49"}
{"id": "33a1dbc3-24c9-47cb-9f82-1aeb6364b3b4", "conversation": "Starlette CORS Forwarding App\n08a446e2-51a2-4abe-89ed-64b7887e12a0", "author_role": "assistant", "content": "To build a web app in Python using the Starlette framework with CORS enabled, you need to follow these steps:\n\n1. Install the required packages: Starlette, HTTPX, and python-dotenv\n2. Create a `.env` file to store the environment variable for the target server\n3. Write the main application script\n\nHere's a step-by-step guide:\n\n1. Install the required packages:\n\nCreate a virtual environment (optional, but recommended) and then run:\n\n```bash\npip install starlette httpx python-dotenv uvicorn aiohttp\n```\n\n2. Create a `.env` file to store the environment variable for the target server:\n\nCreate a `.env` file in the same directory as your main application script, and add the following line:\n\n```\nTARGET_SERVER_HOST=http://your-target-server.com\n```\n\nReplace `http://your-target-server.com` with the actual target server host.\n\n3. Write the main application script:\n\nCreate a new Python file, `main.py`, and add the following code:\n\n```python\nfrom starlette.applications import Starlette\nfrom starlette.middleware import Middleware\nfrom starlette.middleware.cors import CORSMiddleware\nfrom starlette.routing import Route\nfrom starlette.requests import Request\nfrom starlette.responses import JSONResponse\nfrom starlette.config import Config\nimport httpx\nfrom aiohttp.client_exceptions import ClientConnectorError\nimport json\n\nconfig = Config(\".env\")\nTARGET_SERVER_HOST = config(\"TARGET_SERVER_HOST\")\n\nmiddleware = [\n    Middleware(\n        CORSMiddleware,\n        allow_origins=[\"*\"],\n        allow_credentials=True,\n        allow_methods=[\"*\"],\n        allow_headers=[\"*\"],\n    )\n]\n\napp = Starlette(middleware=middleware)\n\n\nasync def forward_request(request: Request):\n    try:\n        async with httpx.AsyncClient() as client:\n            target_url = f\"{TARGET_SERVER_HOST}{request.url.path}\"\n            method = request.method\n            headers = dict(request.headers)\n            if \"host\" in headers:\n                del headers[\"host\"]\n            if request.method in [\"POST\", \"PUT\", \"PATCH\"]:\n                request_body = await request.json()\n            else:\n                request_body = None\n\n            response = await client.request(\n                method, target_url, headers=headers, json=request_body\n            )\n            return JSONResponse(response.json(), status_code=response.status_code)\n    except ClientConnectorError:\n        return JSONResponse({\"error\": \"Target server connection error.\"}, status_code=503)\n    except Exception as e:\n        return JSONResponse({\"error\": str(e)}, status_code=500)\n\n\napp.add_route(\"/{path:path}\", forward_request, methods=[\"GET\", \"POST\", \"PUT\", \"PATCH\", \"DELETE\"])\n\nif __name__ == \"__main__\":\n    import uvicorn\n\n    uvicorn.run(app, host=\"0.0.0.0\", port=8000)\n```\n\nTo run the app, execute the following command:\n\n```bash\nuvicorn main:app --reload\n```\n\nThis will start the Starlette server with CORS enabled, and it will forward all incoming requests to the server host specified in the `.env` file.", "create_time": "2023-03-26 04:12:11"}
{"id": "81860729-2e12-4fc5-87b9-858315b0b0b5", "conversation": "Starlette CORS Forwarding App\n08a446e2-51a2-4abe-89ed-64b7887e12a0", "author_role": "user", "content": "Rewrite that to use os.environ", "create_time": "2023-03-26 04:19:27"}
{"id": "296feb16-86a1-4fde-9c73-fc81b03fe0cd", "conversation": "Starlette CORS Forwarding App\n08a446e2-51a2-4abe-89ed-64b7887e12a0", "author_role": "assistant", "content": "Here's the updated version of `main.py` using `os.environ` instead of `python-dotenv`:\n\n```python\nimport os\nfrom starlette.applications import Starlette\nfrom starlette.middleware import Middleware\nfrom starlette.middleware.cors import CORSMiddleware\nfrom starlette.routing import Route\nfrom starlette.requests import Request\nfrom starlette.responses import JSONResponse\nimport httpx\nfrom aiohttp.client_exceptions import ClientConnectorError\nimport json\n\nTARGET_SERVER_HOST = os.environ.get(\"TARGET_SERVER_HOST\")\n\nmiddleware = [\n    Middleware(\n        CORSMiddleware,\n        allow_origins=[\"*\"],\n        allow_credentials=True,\n        allow_methods=[\"*\"],\n        allow_headers=[\"*\"],\n    )\n]\n\napp = Starlette(middleware=middleware)\n\nasync def forward_request(request: Request):\n    try:\n        async with httpx.AsyncClient() as client:\n            target_url = f\"{TARGET_SERVER_HOST}{request.url.path}\"\n            method = request.method\n            headers = dict(request.headers)\n            if \"host\" in headers:\n                del headers[\"host\"]\n            if request.method in [\"POST\", \"PUT\", \"PATCH\"]:\n                request_body = await request.json()\n            else:\n                request_body = None\n\n            response = await client.request(\n                method, target_url, headers=headers, json=request_body\n            )\n            return JSONResponse(response.json(), status_code=response.status_code)\n    except ClientConnectorError:\n        return JSONResponse({\"error\": \"Target server connection error.\"}, status_code=503)\n    except Exception as e:\n        return JSONResponse({\"error\": str(e)}, status_code=500)\n\napp.add_route(\"/{path:path}\", forward_request, methods=[\"GET\", \"POST\", \"PUT\", \"PATCH\", \"DELETE\"])\n\nif __name__ == \"__main__\":\n    import uvicorn\n\n    uvicorn.run(app, host=\"0.0.0.0\", port=8000)\n```\n\nBefore running the app, you need to set the environment variable `TARGET_SERVER_HOST` in your terminal:\n\nFor Linux/Mac:\n\n```bash\nexport TARGET_SERVER_HOST=http://your-target-server.com\n```\n\nFor Windows:\n\n```cmd\nset TARGET_SERVER_HOST=http://your-target-server.com\n```\n\nReplace `http://your-target-server.com` with the actual target server host. Then run the app with:\n\n```bash\nuvicorn main:app --reload\n```\n\nThe server will start with CORS enabled and forward all incoming requests to the server host specified in the environment variable.", "create_time": "2023-03-26 04:20:17"}
{"id": "e276c040-0bbb-4d2b-9b13-b2f4d676ceee", "conversation": "Starlette CORS Forwarding App\n08a446e2-51a2-4abe-89ed-64b7887e12a0", "author_role": "user", "content": "Catch httpx.HTTPError as the only exception you care about", "create_time": "2023-03-26 04:20:46"}
{"id": "e36825f0-d641-4578-88da-cbd0f26303b3", "conversation": "Starlette CORS Forwarding App\n08a446e2-51a2-4abe-89ed-64b7887e12a0", "author_role": "assistant", "content": "Here's the updated version of `main.py` with only `httpx.HTTPError` as the exception we care about:\n\n```python\nimport os\nfrom starlette.applications import Starlette\nfrom starlette.middleware import Middleware\nfrom starlette.middleware.cors import CORSMiddleware\nfrom starlette.routing import Route\nfrom starlette.requests import Request\nfrom starlette.responses import JSONResponse\nimport httpx\n\nTARGET_SERVER_HOST = os.environ.get(\"TARGET_SERVER_HOST\")\n\nmiddleware = [\n    Middleware(\n        CORSMiddleware,\n        allow_origins=[\"*\"],\n        allow_credentials=True,\n        allow_methods=[\"*\"],\n        allow_headers=[\"*\"],\n    )\n]\n\napp = Starlette(middleware=middleware)\n\nasync def forward_request(request: Request):\n    try:\n        async with httpx.AsyncClient() as client:\n            target_url = f\"{TARGET_SERVER_HOST}{request.url.path}\"\n            method = request.method\n            headers = dict(request.headers)\n            if \"host\" in headers:\n                del headers[\"host\"]\n            if request.method in [\"POST\", \"PUT\", \"PATCH\"]:\n                request_body = await request.json()\n            else:\n                request_body = None\n\n            response = await client.request(\n                method, target_url, headers=headers, json=request_body\n            )\n            return JSONResponse(response.json(), status_code=response.status_code)\n    except httpx.HTTPError as e:\n        return JSONResponse({\"error\": str(e)}, status_code=500)\n\napp.add_route(\"/{path:path}\", forward_request, methods=[\"GET\", \"POST\", \"PUT\", \"PATCH\", \"DELETE\"])\n\nif __name__ == \"__main__\":\n    import uvicorn\n\n    uvicorn.run(app, host=\"0.0.0.0\", port=8000)\n```\n\nNow, the application will only catch `httpx.HTTPError` exceptions and return a JSON response with the error message and a 500 status code.", "create_time": "2023-03-26 04:21:28"}