Unable to Pass Image Parameter to replicate gfpgan/api in Flutter: Input Validation Error 422

I am integrating the gfpgan/api from replicate (Official documentation : https://replicate.com/tencentarc/gfpgan) into my Flutter application to allow users to enhance their images. However, I'm encountering issues with sending the image in the request body. I have tried multiple approaches mentioned in the API documentation, but none of them seem to work.

Here are the methods I've tried:

1. Using the image file path directly:

final predictionUrl = 'https://api.replicate.com/v1/predictions';
final imgValue = imageFile != null ? Uri.file(imageFile.path).toString() : "";
print('img value: $imgValue');
final predictionData = {
  'version': modelVersion,
  'input': {'img': imgValue},
};

I tested the generated path and it looks like: file:///C:/Users/pc/Pictures/Intropic.png.

2. Passing the image file path directly.
3. Encoding the image file as base64 and passing it as a string.
4. Passing the image as a stream.

Unfortunately, all of these methods result in the following error:

Prediction request failed: 422
body: {"detail":"- input.img: Does not match format 'uri'\n","status":422,"title":"Input validation failed","invalid_fields":[{"type":…"}

I have also tried a different approach where I successfully generate the input body parameter using the base64-encoded image data:

var input = Uri.dataFromString(base64Encode(fileBytes!), mimeType: 'application/octet-stream').toString();

However, this method throws a different exception:

Prediction input failed validation: {"detail":[{"loc":["body","input","img"],"msg":"not enough values to unpack (expected 2, got…", "status": "failed"}

I would greatly appreciate any guidance or insights into the correct way to pass the input image parameter in the request.

Thank you in advance for your help!

The issue we were facing here was related to how we passed the image in the request body when using the gfpgan/api from replicate. To send the image correctly, we can follow this approach:

1. First, ensure that you have the image file you want to send, and you've imported the necessary libraries:

```
    import 'dart:convert';
    import 'dart:io';
```

   

2. Read the image file as bytes and encode it as a base64 string. This is the part you've already done correctly in your code:

   
```

if (imageFile != null) {
     final fileBytes = await imageFile.readAsBytes();
     final base64Image = base64Encode(fileBytes);
     imgValue = 'data:image/jpeg;base64,$base64Image';
   }

```

   

   This code reads the image file, encodes it as base64, and constructs a data URI (`imgValue`) that you can use in the request.

3. Now, construct your predictionData JSON object correctly, ensuring you provide the `img` key with the `imgValue`:

   
       final predictionUrl = 'https://api.replicate.com/v1/predictions';
       final predictionData = {
         'version': modelVersion,
         'input': {'img': imgValue},
       };