Server response 783 Unexpected Token (Shopify)

Understanding HTTP Status Code 783 (Unexpected Token)

HTTP status code 783, known as "Unexpected Token," occurs when a server is unable to process a request due to an unexpected token in the data sent. This error is commonly encountered in applications built on the Shopify platform. The appearance of this status code can often be attributed to syntax errors in requests or incorrect data formats.

Causes of HTTP Status Code 783

• Errors in Data Format: Issues such as improperly formatted JSON can lead to this error.
• Incorrect Headers or Request Parameters: Missing or improperly specified headers can trigger the status code.
• Data Encoding Problems: Misinterpretation of character encoding can result in an unexpected token error.

Practical Examples of the Error

1. Example with Incorrect JSON:

   This error can arise when there is a missing comma or incorrect use of quotes in JSON data.

   {
       "name": "Product",
       "price": 10.99
       "description": "A great product"
   }
           

   Corrected version:

   {
       "name": "Product",
       "price": 10.99,
       "description": "A great product"
   }
           

2. Example with Incorrect Encoding:

   Improper character encoding can lead to status code 783. For instance, sending data in UTF-8 format while the server expects ISO-8859-1 can cause issues.

   POST /api/products HTTP/1.1
   Content-Type: application/json; charset=ISO-8859-1
   
   {
       "name": "Produçt",  // Incorrect encoding
       "price": 10.99
   }
           

   Corrected version:

   POST /api/products HTTP/1.1
   Content-Type: application/json; charset=UTF-8
   
   {
       "name": "Product",  // Correct encoding
       "price": 10.99
   }
           

3. Example with Missing Required Parameters:

   Omitting mandatory fields in a request can trigger the error. For instance, if a product ID is required but not provided, it can result in a 783 status code.

   POST /api/products HTTP/1.1
   Content-Type: application/json
   
   {
       "price": 10.99  // Missing required parameter "id"
   }
           

   Corrected request:

   POST /api/products HTTP/1.1
   Content-Type: application/json
   
   {
       "id": 12345,
       "price": 10.99
   }
           

Fixing the Error in Different Programming Languages

JavaScript

To resolve the error using the fetch API, ensure that the JSON object is correctly formed and handle potential errors appropriately.

fetch('https://api.example.com/products', {
    method: 'POST',
    headers: {
        'Content-Type': 'application/json'
    },
    body: JSON.stringify({
        name: 'Product',
        price: 10.99
    })
})
.then(response => {
    if (!response.ok) {
        throw new Error('Unexpected Token');
    }
    return response.json();
})
.catch(error => console.error('Error:', error));

Python

Using the requests library, send correctly formatted requests and handle exceptions to validate data.

import requests

data = {
    'name': 'Product',
    'price': 10.99
}

try:
    response = requests.post('https://api.example.com/products', json=data)
    response.raise_for_status()  # Raise an error for bad responses
except requests.exceptions.HTTPError as err:
    print(f'HTTP error occurred: {err}')
except Exception as err:
    print(f'Other error occurred: {err}')

PHP

When using cURL, ensure that data is formatted correctly and responses from the server are handled properly.

$ch = curl_init('https://api.example.com/products');
$data = json_encode(['name' => 'Product', 'price' => 10.99]);

curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_POST, true);
curl_setopt($ch, CURLOPT_HTTPHEADER, ['Content-Type: application/json']);
curl_setopt($ch, CURLOPT_POSTFIELDS, $data);

$response = curl_exec($ch);
if ($response === false) {
    echo 'Curl error: ' . curl_error($ch);
}
curl_close($ch);

Debugging Tools for API Requests

To effectively diagnose issues leading to status code 783, consider using the following tools:

• Browser Developer Console: This tool allows you to check the requests being sent from your web application. You can view details about headers, payloads, and responses.
• API Testing Tools: Applications like Postman or Insomnia provide a user-friendly interface for crafting and testing API requests. They allow for detailed examination of request/response cycles.

Cause	Example	Correction
Data Format Error	Missing comma in JSON	Add the missing comma
Incorrect Encoding	Using wrong charset	Ensure proper charset is set
Missing Parameters	Required field not present	Add the missing parameter

By understanding the potential causes and implementing the suggested fixes, developers can effectively address and resolve HTTP status code 783 in their applications.