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React image upload to FastAPI Unprocessable Entity

I have created an API using FastApi that processes the image uploaded and return the processed image.

Here is the image upload endpoint

@app.post("/predict")
async def root(file: UploadFile = File(...)):
..............................
res,im_png = cv2.imencode(".png", bg_img)
    return StreamingResponse(io.BytesIO(im_png.tobytes()), media_type="image/png")

What I have done in the frontend:

class Detect extends Component {

  state = {
    title: '',
    content: '',
    image: null
  };

  handleChange = (e) => {
    this.setState({
      [e.target.id]: e.target.value
    })
  };

  handleImageChange = (e) => {
    this.setState({
      image: e.target.files[0]
    })
  };

  handleSubmit = (e) => {
    e.preventDefault();
    console.log(this.state);
    let form_data = new FormData();
    form_data.append('image', this.state.image, this.state.image.name);
    let url = 'http://127.0.0.1:8000/predict';
    axios.post(url, form_data, {
      headers: {
        'content-type': 'multipart/form-data'
      }
    })
        .then(res => {
          console.log(res.data);
        })
        .catch(err => console.log(err))
  };

  render() {
    return (
      <div className="App">
        <form onSubmit={this.handleSubmit}>

          <p>
            <input type="file"
                   id="image"
                   accept="image/png, image/jpeg"  onChange={this.handleImageChange} required/>
          </p>
          <input type="submit"/>
        </form>
      </div>
    );
  }
}

export default Detect;

When I upload the image through frontend and submit it the API shows "Unprocessable Entity", while it was working fine when I was using Swagger UI.

What I believe is the image is not being received by the FastApi as a type that it can processed How can I resolve this issue??

over 4 years ago · Santiago Trujillo
1 answers
Answer question

0

You should add your image to the FormData object, using the same key defined in the endpoint for the file upload (in your case, that is, file). Thus, you should do:

form_data.append('file', this.state.image, this.state.image.name);
over 4 years ago · Santiago Trujillo Report
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