You could either encode the image data to Base64 format on server side and return the base64-encoded string, which can then be used to display the image in the HTML page as shown here (e.g., <img src=”data:image/png;base64, …), or send the raw bytes—it might be best not to use a StreamingResponse for sending the raw … Read more
As per FastAPI’s documentation, UploadFile uses Python’s SpooledTemporaryFile, a “file stored in memory up to a maximum size limit, and after passing this limit it will be stored in disk.”. It “operates exactly as TemporaryFile”, which “is destroyed as soon as it is closed (including an implicit close when the object is garbage collected)”. It … Read more
You shouldn’t be using StreamingResponse, as suggested by some other answer. If the entire image bytes are loaded into memory from the beginning (e.g., into an in-memory bytes buffer), using StreamingResponse makes little sense. Please have a look at this answer for more details. You should instead use Response and pass the image bytes, after … Read more
You would need to use a Javascript interface/library such as Fetch API, which allows you to send data in JSON format (example is given below). For submiting Form data instead, have a look at this answer, while for posting both Files and Form/JSON data, have a look at this answer. For the frontend, you could … Read more
Straight from the documentation: The function parameters will be recognized as follows: If the parameter is also declared in the path, it will be used as a path parameter. If the parameter is of a singular type (like int, float, str, bool, etc) it will be interpreted as a query parameter. If the parameter is … Read more
Option 1 – Return image as bytes The below examples show how to convert an image loaded from disk, or an in-memory image (numpy array), into bytes (using either PIL or OpenCV libraries) and return them using a custom Response. For the purposes of this demo, the below code is used to create the in-memory … Read more
You can write the file(s) using synchronous writing , after defining the endpoint with def, as shown in this answer, or using asynchronous writing (utilising aiofiles), after defining the endpoint with async def; UploadFile methods are async methods, and thus, you need to await them. Example is given below. For more details on def vs … Read more
The below examples use the .file attribute of the UploadFile object to get the actual Python file (i.e., SpooledTemporaryFile), which allows you to call its methods, such as .read() and .close(), without having to await them. It is important, however, to define your endpoint with def in this case—otherwise, such operations would block the server … Read more
As per FastAPI’s documentation: When you declare a path operation function with normal def instead of async def, it is run in an external threadpool that is then awaited, instead of being called directly (as it would block the server). Thus, def (sync) routes run in a separate thread from a threadpool, or, in other … Read more
As per FastAPI documentation, You can declare multiple Form parameters in a path operation, but you can’t also declare Body fields that you expect to receive as JSON, as the request will have the body encoded using application/x-www-form-urlencoded instead of application/json (when the form includes files, it is encoded as multipart/form-data). This is not a … Read more