extractJsonFromText function

String extractJsonFromText(String text)

Extracts a valid JSON string from a block of text.

This function looks for a JSON block between ```json and ``` markers and attempts to extract and clean the JSON content.

Parameters:

• text: The raw text containing the JSON.

Returns: A valid JSON string extracted from the input text.

Throws:

• FormatException if valid JSON is not found within the text.

Implementation

String extractJsonFromText(String text) {
  // Find the position of the first ```json``` block
  final jsonStart = text.indexOf('```json');
  // Find the position of the closing ```
  final jsonEnd = text.indexOf('```', jsonStart + 6);

  // Check if both the start and end markers were found
  if (jsonStart != -1 && jsonEnd != -1) {
    // Extract the potential JSON text between the markers
    String jsonString = text.substring(jsonStart + 6, jsonEnd).trim();

    // Now clean up the JSON string to remove any unwanted characters
    // Ensure the string starts with '{' and ends with '}' (valid JSON structure)
    final validJsonStart = jsonString.indexOf('{');
    final validJsonEnd = jsonString.lastIndexOf('}');

    if (validJsonStart != -1 && validJsonEnd != -1) {
      jsonString = jsonString.substring(validJsonStart, validJsonEnd + 1);
      return jsonString;
    } else {
      throw const FormatException(
          "Valid JSON not found within the extracted text");
    }
  } else {
    throw const FormatException("JSON format not found in the response");
  }
}