Build a custom error handling framework to enhance the error handling capabilities of Golang functions

By building a custom error handling framework, you can enhance the error handling capabilities of Go functions: define custom error types and carry additional error information. Create an error handler and return the corresponding response based on the custom error type. Integrate error handlers into functions to flexibly handle different types of errors.

Build a custom error handling framework to enhance the error handling capabilities of Golang functions

Introduction

In the Go language, error handling is crucial to writing robust and maintainable applications. The built-in error type provides a convenient way to represent and propagate errors. However, in some cases, a more flexible and customizable error handling mechanism is required. This article will introduce how to build a custom error handling framework to enhance the error handling capabilities of Go functions.

Error Type

We first define a custom error type that will carry additional information about the error. For example, the following code defines a DatabaseError type that represents a database error:

type DatabaseError struct {
    Message string
    Query string
    Code int
}

func (e DatabaseError) Error() string {
    return fmt.Sprintf("DatabaseError: %s (query: %s, code: %d)", e.Message, e.Query, e.Code)
}

Error() The method returns a formatted error message that contains information about the error Details.

Error Handler

Next, we will create an error handler function that will handle the custom error and return an appropriate response. For example, the following code defines a handler that converts DatabaseError to an HTTP status code:

func HandleDatabaseError(w http.ResponseWriter, r *httpRequest, err error) {
    if dbErr, ok := err.(DatabaseError); ok {
        switch dbErr.Code {
        case 404:
            http.NotFound(w, r)
        case 500:
            http.InternalServerError(w, r)
        default:
            http.BadRequest(w, r)
        }
    } else {
        http.Error(w, "Internal Server Error", 500)
    }
}

Integrated Error Handler

Now, we Error handlers can be integrated into our functions. For example, the following is a function that handles database queries. If DatabaseError is encountered, use the HandleDatabaseError function:

func QueryDatabase(query string) (result []string, err error) {
    // 执行数据库查询

    if err != nil {
        if dbErr, ok := err.(DatabaseError); ok {
            return nil, HandleDatabaseError(err)
        }
        return nil, err
    }

    // 处理成功的结果

    return result, nil
}

Actual case

Consider the following sample code, which uses a custom error handling framework to handle database errors:

package main

import (
    "log"
    "net/http"
    // 自定義的錯誤處理器及其他代碼
)

func main() {
    http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
        result, err := QueryDatabase("SELECT * FROM users")
        if err != nil {
            // 根據錯誤，產生不同的 HTTP 狀態碼
            HandleDatabaseError(w, r, err)
        } else {
            // 處理成功的結果
            fmt.Fprintf(w, "Users: %+v", result)
        }
    })
    log.Fatal(http.ListenAndServe(":8080", nil))
}

Conclusion

By using a custom error handling framework, we Can enhance the error handling capabilities of Go functions. It allows us to define custom error types, create error handlers, and flexibly handle errors based on specific error categories. This helps improve error handling logic, readability, and maintainability.

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