Comprehensive Guide to Network Requests in HarmonyOS: From Permission Configuration to Implementation

I. Network Permission Architecture

1. Permission Configuration Specifications

// module.json5 configuration example
"requestPermissions": [ 
  {
    "name": "ohos.permission.INTERNET", // Core network permission
    "reason": "Access to cloud services required",
    "usedScene": "Data synchronization scenarios"
  },
  {
    "name": "ohos.permission.ACCESS_WIFI_STATE", // WiFi state permission
    "reason": "Optimize network selection strategy"
  }
]

Permission hierarchy mechanism:

System Pre-Grant: INTERNET permission granted by default (system_grant)
Dynamic Grant: User-confirmation required permissions (user_grant), e.g., location access

II. Official Network Request Solutions

1. Native HTTP Module

Implementation Steps:

// 1. Create request object
import http from '@ohos.net.http';
let httpRequest = http.createHttp();

// 2. Configure request parameters
const options = {
  method: http.RequestMethod.GET,
  url: "https://api.example.com/data",
  header: { "Content-Type": "application/json" },
  connectTimeout: 10000,
  readTimeout: 15000
}

// 3. Send request
httpRequest.request(options, (err, data) => {
  if(!err) {
    console.log(JSON.parse(data.result as string));
  }
});

// 4. Resource cleanup
httpRequest.destroy();

Core Features:

Protocol support: HTTP/1.1 (including WebSocket)
Connection management: Automatic TCP connection reuse
Caching strategy: Memory + disk two-tier caching

2. Axios Porting Solution

# Install axios
ohpm i @ohos/axios

import axios from '@ohos/axios';

// Create instance
const instance = axios.create({
  baseURL: 'https://api.example.com',
  timeout: 5000
})

// Interceptor configuration
instance.interceptors.request.use(config => {
  config.headers.Authorization = `Bearer ${token}`;
  return config;
});

Feature Comparison:

Feature	Native HTTP	Axios
Type Support	Manual parsing required	Automatic JSON conversion
Interceptors	Custom implementation needed	Built-in interceptors
Error Handling	Callback functions	Promise chaining
File Upload	Manual handling	FormData support

III. Underlying Implementation Principles

1. Network Stack Architecture

Application Layer
└── Network APIs (HTTP/WebSocket)
    └── Network Service Framework (NetService)
        └── Network Protocol Stack (TCP/IP)
            └── Hardware Abstraction Layer (Network Drivers)

2. Key Technical Components

Connection Pool Management: Maintains 4 persistent connections by default
DNS Resolution: Local cache + system-level resolution
Certificate Validation: System CA certificate storage
Traffic Monitoring: NetworkKit API integration

IV. Advanced Implementation Scenarios

1. WebSocket Communication

import { WebSocket } from '@ohos.net.websocket';

const ws = new WebSocket('wss://echo.websocket.org');
ws.onopen = () => {
  ws.send('Hello Server');
}
ws.onmessage = (event) => {
  console.log(event.data);
}

2. Resumable File Upload

const uploadFile = async (filePath: string) => {
  const file = await fileio.open(filePath, fileio.OpenMode.READ);
  const totalSize = await fileio.stat(filePath).then(stat => stat.size);

  let uploaded = 0;
  while(uploaded < totalSize) {
    const chunk = await file.read(totalSize - uploaded, 1024 * 1024);
    await http.post('https://api/upload', {
      header: { 'Content-Range': `bytes ${uploaded}-${uploaded+1023}` }
    }, chunk);
    uploaded += 1024 * 1024;
  }
}

V. Performance Optimization Strategies

1. Connection Reuse Configuration

// In ApplicationAbility
class MyAbility extends Ability {
  onInit() {
    const config = {
      maxConnectionsPerRoute: 6,
      connectionTimeout: 15000,
      socketOptions: {
        soKeepAlive: true,
        tcpNoDelay: true
      }
    };
    NetworkManager.getInstance().setGlobalConfig(config);
  }
}

2. Caching Optimization

const cacheConfig = {
  policy: CachePolicy.CACHE_FIRST,
  maxAge: 3600, // 1 hour cache
  storage: {
    path: '/data/cache',
    maxSize: 1024 * 1024 * 50 // 50MB
  }
}

http.setRequestCacheConfig(cacheConfig);

VI. Debugging & Monitoring

1. Network Sniffing

# Start packet capture
deveco-cli network-sniffer --port=8080

2. Performance Metrics

Metric	Target	Monitoring Method
DNS Resolution Time	<100ms	NetworkProfiler
TCP Handshake Latency	<200ms	DevTools Network Panel
TTFB (Time to First Byte)	<500ms	Performance API
Total Request Time	<1500ms	Resource Timing API

VII. Implementation Recommendations

Connection Lifecycle Management:
Always call destroy() to release resources promptly
Retry Mechanism Design:
Implement exponential backoff strategy (maxRetries=3)
Security Enhancements:

   // Enforce HTTPS
   const secureOptions = {
     httpsOnly: true,
     certificatePinner: {
       pins: ['sha256/AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA=']
     }
   }

Multi-environment Configuration:

   const env = process.env.NODE_ENV;
   const baseURL = env === 'production' 
     ? 'https://api.prod.com' 
     : 'https://api.dev.com';

This comprehensive guide provides a complete framework for building reliable network modules in HarmonyOS. Developers are recommended to utilize DevEco Studio's Network Profiler for real-time performance optimization and consider hybrid solutions combining Axios with native modules for complex scenarios.

魔眼天王 @moyantianwang