zzyxyz_server/static/fetch-wrapper.js

class FetchWrapper {
    constructor(baseURL, options = {}, contentTypeMappings = {}, onError = console.error) {
        this.baseURL = baseURL;
        this.contentTypeMappings = contentTypeMappings;
        this.defaultContentType = 'application/json';
        this.onError = onError;
        this.defaultOptions = {
            ...{
                method: 'GET',
                headers: new Headers({
                    'Content-Type': this.defaultContentType
                }),
                mode: 'cors', // 指定是否允许跨域请求，默认为cors
                cache: 'default', // 请求的缓存模式
                credentials: 'same-origin', // 请求的凭据模式，默认同源请求时发送cookies
                parseResponseHandler: {
                    'application/json': response => response.json(),
                    'text/*': response => response.text(),
                    'image/*': response => response.blob(),
                    'application/octet-stream': response => response.blob(),
                    '*/*': response => response.arrayBuffer(), // 默认处理程序
                },
                ...options
            }
        };
    }



    async fetch(url, options = {}) {
        // 合并默认选项与传入的options
        const mergedOptions = { ...this.defaultOptions, ...options };

        // 根据URL自动设置Content-Type（如果有匹配的映射）
        const matchedMapping = Object.entries(this.contentTypeMappings).find(([pattern, type]) => url.endsWith(pattern));
        if (matchedMapping && !mergedOptions.headers.has('Content-Type')) {
            mergedOptions.headers['Content-Type'] = matchedMapping[1];
        }
        // 根据请求方法处理数据
        if (['POST', 'PUT', 'PATCH'].includes(mergedOptions.method)) {
            if (typeof mergedOptions.body === 'object') {
                mergedOptions.body = JSON.stringify(mergedOptions.body);
                // 如果Content-Type未设置或默认为application/json，则需要在这里设置
                if (!mergedOptions.headers.has('Content-Type')) {
                    mergedOptions.headers.set('Content-Type', 'application/json');
                }
            } else if (mergedOptions.body !== null && typeof mergedOptions.body !== 'string') {
                throw new Error('非GET请求时, body必须是一个对象或字符串');
            }
        } else if (mergedOptions.method === 'GET' && mergedOptions.body) {
            console.warn('GET请求不支持发送请求体, 已忽略提供的body参数');
            delete mergedOptions.body;
        }

        url = new URL(url, this.baseURL).href;

        return fetch(url, mergedOptions)
            .then(async response => {
                if (!response.ok) {
                    throw new Error(`HTTP error! status: ${response.status}`);
                    // console.warn(`HTTP warning! status: ${response.status}`);
                }

                const contentType = response.headers.get('content-type').split(';')[0].trim();
                const parseResponseHandler = this.getParseResponseHandler(contentType);

                const responseData = await parseResponseHandler(response);
                return formatResponse(response, responseData);
            })
            .catch(error => {
                error.options = mergedOptions;
                error.url = url;
                error.timestamp = Date.now();
                error.onFunction = 'fetch';
                this.onError(error.message);
                throw error;
            });
    }

    getParseResponseHandler(contentType) {
        if (contentType.startsWith('text/')) {
            return this.defaultOptions.parseResponseHandler['text/*'] || this.defaultOptions.parseResponseHandler['*/*'];
        }
        if (contentType.startsWith('image/')) {
            return this.defaultOptions.parseResponseHandler['image/*'] || this.defaultOptions.parseResponseHandler['*/*'];
        }
        return this.defaultOptions.parseResponseHandler[contentType] || this.defaultOptions.parseResponseHandler['*/*'];
    }

    async fetchWithRetry(url, options = {}, maxRetries = 3, retryDelayBaseMs = 1000) {
        let remainingAttempts = maxRetries;
        const delays = [];

        for (let i = 0; i < maxRetries; i++) {
            delays.push(retryDelayBaseMs * Math.pow(2, i));
        }

        const attemptFetch = async (retryIndex = 0) => {
            try {
                return await this.fetch(url, options);
            } catch (error) {
                if (remainingAttempts > 1) {
                    console.log(`请求失败，剩余重试次数：${remainingAttempts - 1}`);
                    setTimeout(() => attemptFetch(retryIndex + 1), delays[retryIndex]);
                    remainingAttempts--;
                    return;
                } else {
                    this.onError(error.message);
                    throw error;
                }
            }
        };

        return attemptFetch();
    }

    // 可以为不同的HTTP方法提供便捷的方法，如：
    async post(url, body, options = {}) {
        return this.fetch(url, { ...options, method: 'POST', body });
    }

    async get(url, options = {}) {
        return this.fetch(url, { ...options, method: 'GET' });
    }

    async put(url, body, options = {}) {
        return this.fetch(url, { ...options, method: 'PUT', body });
    }

    async patch(url, body, options = {}) {
        return this.fetch(url, { ...options, method: 'PATCH', body });
    }

    async delete(url, options = {}) {
        return this.fetch(url, { ...options, method: 'DELETE' });
    }
};

function formatResponse(response, data) {
    return {
        status: response.status,
        message: response.statusText,
        data,
    };
}

// 检查是否在Node.js环境中
if (typeof module !== 'undefined' && typeof module.exports !== 'undefined') {
    // Node.js环境，使用CommonJS
    module.exports = FetchWrapper;
} else if (typeof window !== 'undefined') {
    // 浏览器环境，直接暴露到全局作用域（不推荐，但简单示例）
    // window.FetchWrapper = FetchWrapper;
}