WeChat payment development process, WeChat payment development process_PHP tutorial

WeChat payment development process, WeChat payment development process

It is better to teach a man to fish than to teach him to fish

WeChat payment development process

The following uses PHP language as an example to explain the development process of WeChat payment.

1. Get order information

2. Generate sign based on order information and payment-related account number, and generate payment parameters

3. POST the payment parameter information to the WeChat server and obtain the return information

4. Generate the corresponding payment code (within WeChat) or payment QR code (not within WeChat) based on the returned information to complete the payment.

The following is a step-by-step explanation:

1. There are three necessary order parameters related to WeChat payment, namely: body (product name or order description), out_trade_no (usually order number) and total_fee (order amount, unit "cent", pay attention to the unit Question), in different applications, the first thing to do is to obtain the relevant information in the order to prepare for the generation of payment parameters.

2. Other necessary payment parameters include appid (WeChat appid), mch_id (notified after the application is successful), device_info (the parameters on the web and WeChat sides are the same, capitalized "WEB"), trade_type (according to This value is also different in different usage scenarios. It is "NATIVE" outside WeChat and "JSAPI" inside WeChat), nonce_str (32-bit random string), spbill_create_ip (the terminal IP that initiates the payment, that is, the server IP), notify_url (payment Callback address, the WeChat server notifies the website whether the payment is completed or not, modify the order status), sign (signature), and there is another point that needs to be explained. If trade_type is JSAPI, openid is a required parameter.

The signature algorithm is prone to errors because the signing steps are cumbersome. In fact, the most important thing is that sign does not participate in the signature

A: Assign the parameters mentioned in 1 and 2 except sign into an array array, and sort them in dictionary order. In fact, the key values ​​are sorted in the order of A-Z.

B: Convert the array into a string string in the format k1=v1&k2=v2&...kN=vN

C: Add the KEY value after this string (set by the user in the WeChat payment merchant backend). Now string = k1=v1&k2=v2&...kN=vN&key=KEY.

D：string = md5(string)

E: sign = strtoupper(string)

At this point, the sign is generated.

Add sign to the array array to generate a new array. Convert this array to XML. At this point, the parameter preparation work for WeChat payment is completed.

3. Use POST to send the XML generated in 2 to WeChat (https://api.mch.weixin.qq.com/pay/unifiedorder), obtain the returned XML information, and convert the information into array format for easy operation. The returned XML information is as follows:

<xml>
   <return_code><![CDATA[SUCCESS]]></return_code>
   <return_msg><![CDATA[OK]]></return_msg>
   <appid><![CDATA[wx2421b1c4370ec43b]]></appid>
   <mch_id><![CDATA[10000100]]></mch_id>
   <nonce_str><![CDATA[IITRi8Iabbblz1Jc]]></nonce_str>
   <sign><![CDATA[7921E432F65EB8ED0CE9755F0E86D72F]]></sign>
   <result_code><![CDATA[SUCCESS]]></result_code>
   <prepay_id><![CDATA[wx201411101639507cbf6ffd8b0779950874]]></prepay_id>
   <trade_type><![CDATA[JSAPI]]></trade_type>
</xml>

If it is trade_type==native payment, there will be an additional parameter code_url, which is the address of WeChat scan code payment.

4. The following is the payment process.

If trade_type==native, then use some methods to convert the code_url into a QR code, and just use WeChat to scan the code. If it is click-to-pay within WeChat, you need to call the relevant things in WeChat js-sdk. This step The most important thing is to generate a string in json format.

First, generate the array_jsapi that converts the json string.

A: The parameters of this array include: appId, timeStamp, nonceStr, package, signType (default is "MD5"). Please note that the case is different from the above array.

B: Use this array to generate paySign parameters. The signature method is the same as above.

C: Append the paySign parameter to the array_jsapi array.

D: Format the array into a string js_string using json_encode.

After completing the above work, you can make payment within WeChat.

The following is a sample code for related payments:

<script type='text/javascript'>
	                                function jsApiCall()
					{
						WeixinJSBridge.invoke(
							'getBrandWCPayRequest',
							$js_string,
							function(res){
								WeixinJSBridge.log(res.err_msg);
									if(res.err_msg=='get_brand_wcpay_request:ok')
									{
										alert('支付成功');
									}
									else
									{
										alert('支付失败');
									}
							}
						);
					}
					function callpay()
					{
						if (typeof WeixinJSBridge == 'undefined'){
						    if( document.addEventListener ){
						        document.addEventListener('WeixinJSBridgeReady', jsApiCall, false);
						    }else if (document.attachEvent){
						        document.attachEvent('WeixinJSBridgeReady', jsApiCall); 
						        document.attachEvent('onWeixinJSBridgeReady', jsApiCall);
						    }
						}else{
						    jsApiCall();
						}
					}
				</script>

The js_string in the code is the string we generated.

Call the callpay() function in HTML code to initiate payment.

In this way, the payment work of WeChat Pay is completed.

The following is the callback work. This function ensures that the correct status is displayed to the user after the order payment is successful.

After the payment is completed, WeChat uses a POST request to feedback the payment results to the website server. The website server obtains the POST information and determines whether to modify the order information based on whether the payment is successful or not.

A: Remove the sign in the POST parameter and record the value.

B: Sign the remaining parameters

C: Compare the signature result with the sign in POST. If the signature is the same, it means the signature is correct. Modify the order status according to the payment result.

E: Return XML information to WeChat to ensure that WeChat knows that the website has received the notification and prevent WeChat from pushing POST again. The example is as follows:

<xml>
  <return_code><![CDATA[SUCCESS]]></return_code>
  <return_msg><![CDATA[OK]]></return_msg>
</xml>

If failed, return

<xml>
  <return_code><![CDATA[FAIL]]></return_code>
  <return_msg><![CDATA[失败原因]]></return_msg>
</xml>

At this point, the entire development of WeChat Payment is introduced.

If you have any questions, please contact QQ: 97695870