JSON to JSONP: cross-domain request proxy IP integration detailed step-by-step tutorials

Hands-on with JSONP to bypass cross-domain restrictions

Do you do the old iron of web development, certainly have encountered cross-domain request by the browser to intercept the bad things. Today we will use the most grounded way, say how to use proxy IP with JSONP to solve this problem.

First, the first whole understand what is JSONP

Simply put, JSONP is alit. save the country by curving the path to disasterThe method. Browsers don't allow taking data directly across domains, but they do allow loading external scripts. For example, you can write this in a web page:

<script src="https://api.example.com/data?callback=handleData"></script>

The server returns a function call:handleData({"name": "Zhang San"}). This way the front-end can get the data directly, which is the JSONPCore gameplayThe

Second, why do you want to use a proxy IP to get involved in this?

Many sites are now addingIP access frequency limitationIf you are not able to do so, you will be blocked if you request directly from your own server's IP. At this time it is necessary:

• Rotate different regional IPs to avoid restrictions
• Hide the real server address
• Breaking regional access restrictions for certain APIs

To cite a practical scenario: you want to capture the price data of an e-commerce platform, the IP of your own server with 50 consecutive requests will be blacked out, this time you need a proxy IP pool tocover upThe

III. Four steps for concrete operation

Step 1: Register for a ipipgo account
Go to the website and pick one.Static Home Package, 35 bucks for an IP will last you a month. It is recommended to buy 3 IPs first to do a rotation test.

Step 2: Get API access information
Find a connection message similar to this on the console:

Proxy server: gateway.ipipgo.com
Port: 9021
Account: user123
Password: pass456

Step 3: Configure the proxy on the server side
Take Node.js, for example, and use thehttp-proxyThe library does an intermediate forward:

const proxy = require('http-proxy').createProxyServer();

app.get('/proxy-api', (req, res) => {
  proxy.web(req, res, {
    target: 'https://目标网站.com',
    auth: 'user123:pass456',
    headers: {
      'X-Real-IP': 'Randomly generated proxy IP'
    }
  });
}).

Step 4: Front-end JSONP calls
Dynamically create script tags in web pages:

function handleData(data) {
  console.log('Received data:', data); }
}

const script = document.createElement('script'); script.src = ''; }
script.src = 'https://你的域名/proxy-api?callback=handleData'; document.body.appendChild()
document.body.appendChild(script); } const script = document.createElement('script')

IV. Guidelines for avoiding pitfalls

Q: What should I do if the returned data keeps reporting syntax errors?
A: Check if the server side returns the correct function call format, such ashandleData({"code":200})Instead of pure JSON

Q: What should I do if the proxy IP connection times out?
A: Switching in the ipipgo consoleTK Line套餐，专线通道能降到200ms以内

Q: How to determine whether the proxy IP is effective?
A: Look in the server-side logs for the request header in thex- forwarded- forfield, it's just fine to show a proxy IP

v. ipipgo's unique skills

One last tip: add theFailure Retry MechanismWhen a proxy IP fails, it automatically switches to the next one. This with ipipgo's IP pool, basically can realize 7 × 24 hours stable operation. If you don't understand, you can directly look for their technical customer service, the response speed is much faster than peers.