Ошибки кодирования в запросах GraphQL из Delphi 5: исправления и современные решения

Delphi , Интернет и Сети , URL

Title: Resolving GraphQL Encoding Issues in Delphi 5 Applications

Introduction

Delphi 5, a powerful development tool, can sometimes encounter content encoding issues when sending GraphQL requests to third-party APIs. This article aims to address these issues and provide modern solutions to resolve them.

Understanding the Problem

The original problem was reported by a user who was experiencing a syntax error in their GraphQL request when using Delphi 5 to send a POST request to a PHP API, which in turn communicates with a GraphQL API. The issue was that the query string was being broken with numerous '+' signs, leading to a parsing error.

Delphi 5 and Indy v10.1.5

It's essential to note that Delphi 5 is quite outdated, and using Indy v10.1.5, which is also ancient, can lead to compatibility and functionality issues. It's highly recommended to upgrade to a newer version of Delphi and Indy for better performance and support.

The Delphi Code

The user provided the following Delphi code that was not working:

procedure TForm1.ExportaClassApp(prID : Integer; prNumBoleto, prLinhaDigitavel : String);
begin
  // ... (rest of the code)
  sRetornoClassApp := oHTTP.URL.URLDecode(oHTTP.Get(Url_Completa));
  // ... (rest of the code)
end;

Potential Issues and Solutions

1. Instantiating two TIdHTTP objects: The code instantiates two TIdHTTP objects but only uses one. The other object is leaked. To fix this, ensure that only one TIdHTTP object is created and used.

2. Using StringReplace for URL encoding: The code uses StringReplace to encode the URL query parameters, which is not the recommended approach. Instead, use TIdURI.ParamsEncode to properly encode the parameters.

3. Decoding the response: The code attempts to decode the response using TIdURI.URLDecode, which is not necessary. The response should be used as-is.

4. GET vs POST: The user mentioned that they tried both GET and POST requests, but the provided code only shows a GET request. Ensure that the correct HTTP verb is used based on the API's requirements.

Modern Solutions

To resolve the content encoding issues, consider the following solutions:

1. Upgrade to a newer version of Delphi and Indy: As mentioned earlier, using outdated tools can lead to various issues. Upgrading to a modern version of Delphi and Indy can help resolve many of the encountered problems.

2. Use TIdURI for URL encoding and decoding: Instead of manually encoding and decoding the URL, use TIdURI.ParamsEncode and TIdURI.URLDecode to ensure proper encoding and decoding.

3. Apply URL encoding only to accentuated strings: The user found that the problem only occurred with strings containing accentuation. Apply the URL encoding function only to variables that may contain accentuation to minimize unnecessary encoding.

4. Remove the second TIdHTTP instance: Ensure that only one TIdHTTP object is created and used to avoid memory leaks.

Conclusion

Resolving GraphQL encoding issues in Delphi 5 applications requires a combination of understanding the underlying problem, identifying potential issues in the code, and applying modern solutions. By upgrading to a newer version of Delphi and Indy, using proper URL encoding and decoding functions, applying URL encoding only to accentuated strings, and removing unnecessary TIdHTTP instances, developers can successfully address these content encoding problems and ensure smooth communication with third-party GraphQL APIs.

Создано по материалам из источника по ссылке.

Статья о решении проблем с кодированием в Delphi 5 при отправке запросов GraphQL.

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