How to upload file using fastapi with vue? I got error unprocessable 422

ghz 1years ago ⋅ 3354 views

Question

I am try to upload a file into a directory, I am using vue.js and fastapi in Python.

But every time I get an error 422 unprocessable function.

I tried to use the official doc like this:

<!-- Vue Template --> 

<input
    style="display: none"
    type="file"
    name="files"
    ref="fileAdd"
    v-on:change="handleFilesChange()"
/>



// Vue Script

handleFilesChange() {
    var uploadedFiles = this.$refs.fileAdd.files;
    if (uploadedFiles.length > 0) {
      for (var i = 0; i < uploadedFiles.length; i++) {
        this.files.push(uploadedFiles[i]);

        var formData = new FormData();
        formData.append("files", this.$refs.fileAdd.files[0]);
        axios
          .post(url + "/uploadfile", formData, {
            headers: {
              "Content-Type": "multipart/form-data",
            },
            onUploadProgress: (uploadStatus) => {
              this.uploadProgress = Math.round(
                (uploadStatus.loaded / uploadStatus.total) * 100
              );
              this.isUplading = true;
            },
          })
          .then((response) => {do something}
        }
    }
}



# FastAPI endpoint

@app.post('/uploadfile')
async def upload_file(sid: str, files: List[UploadFile]=File(...)):
    print(files)
    if(files == []):
        print("No Files")
    else:
        print(files[0].filename)
    #...do something

and I got error 422 unprocessable.

Any idea how to solve this problem?

Answer

I'm not a vuejs expert (nor javascript), but I think the problem is what you are passing to axios:

formData.append("files", this.$refs.fileAdd.files[0]);

with the above line, you are (as far as I've understood vuejs and your code), a single file (the [0]) instead of an array of files.

The idea is to pass an array of files, which I guess could be achieved as follows:

formData.append("files", this.$refs.fileAdd.files); or

formData.append("files", [this.$refs.fileAdd.files[0]]);

A similar question has been already asked and answered, so it may be worth giving it a look [How can I upload multiple files using JavaScript and FastAPI?](https://stackoverflow.com/questions/65510798/how-can-i-upload- multiple-files-using-javascript-and-fastapi/65513660#65513660)

#fastapi