手把手教你iOS微信支付

和支付宝一样，先去开放平台下载SDK和开发文档，然后添加依赖和framework，按照文档一步一步来。

• 和支付宝不同的是，微信支付需要两次签名，这两次签名可以都放在服务器端进行，也可以第一次在服务器第二次在app,或者都在app端进行

首先需要走自己接口获取签名，传入订单号和IP
IP的话，需要注意WIFI和4G,因为我之前测试的时候一直用的WIFI，然后换成4G,获取不到IP地址。

#pragma mark - 获取设备当前网络IP地址
- (NSString *)getIPAddress:(BOOL)preferIPv4
{
    NSArray *searchArray = preferIPv4 ?
    @[ IOS_VPN @"/" IP_ADDR_IPv4, IOS_VPN @"/" IP_ADDR_IPv6, IOS_WIFI @"/" IP_ADDR_IPv4, IOS_WIFI @"/" IP_ADDR_IPv6, IOS_CELLULAR @"/" IP_ADDR_IPv4, IOS_CELLULAR @"/" IP_ADDR_IPv6 ] :
    @[ IOS_VPN @"/" IP_ADDR_IPv6, IOS_VPN @"/" IP_ADDR_IPv4, IOS_WIFI @"/" IP_ADDR_IPv6, IOS_WIFI @"/" IP_ADDR_IPv4, IOS_CELLULAR @"/" IP_ADDR_IPv6, IOS_CELLULAR @"/" IP_ADDR_IPv4 ] ;
    
    NSDictionary *addresses = [self getIPAddresses];
    NSLog(@"addresses: %@", addresses);
    
    __block NSString *address;
    [searchArray enumerateObjectsUsingBlock:^(NSString *key, NSUInteger idx, BOOL *stop)
     {
         address = addresses[key];
         //筛选出IP地址格式
         if([self isValidatIP:address]) *stop = YES;
     } ];
    return address ? address : @"0.0.0.0";
}

- (BOOL)isValidatIP:(NSString *)ipAddress {
    if (ipAddress.length == 0) {
        return NO;
    }
    NSString *urlRegEx = @"^([01]?\\d\\d?|2[0-4]\\d|25[0-5])\\."
    "([01]?\\d\\d?|2[0-4]\\d|25[0-5])\\."
    "([01]?\\d\\d?|2[0-4]\\d|25[0-5])\\."
    "([01]?\\d\\d?|2[0-4]\\d|25[0-5])$";
    
    NSError *error;
    NSRegularExpression *regex = [NSRegularExpression regularExpressionWithPattern:urlRegEx options:0 error:&error];
    
    if (regex != nil) {
        NSTextCheckingResult *firstMatch=[regex firstMatchInString:ipAddress options:0 range:NSMakeRange(0, [ipAddress length])];
        
        if (firstMatch) {
            NSRange resultRange = [firstMatch rangeAtIndex:0];
            NSString *result=[ipAddress substringWithRange:resultRange];
            //输出结果
            NSLog(@"%@",result);
            return YES;
        }
    }
    return NO;
}

- (NSDictionary *)getIPAddresses
{
    NSMutableDictionary *addresses = [NSMutableDictionary dictionaryWithCapacity:8];
    
    // retrieve the current interfaces - returns 0 on success
    struct ifaddrs *interfaces;
    if(!getifaddrs(&interfaces)) {
        // Loop through linked list of interfaces
        struct ifaddrs *interface;
        for(interface=interfaces; interface; interface=interface->ifa_next) {
            if(!(interface->ifa_flags & IFF_UP) /* || (interface->ifa_flags & IFF_LOOPBACK) */ ) {
                continue; // deeply nested code harder to read
            }
            const struct sockaddr_in *addr = (const struct sockaddr_in*)interface->ifa_addr;
            char addrBuf[ MAX(INET_ADDRSTRLEN, INET6_ADDRSTRLEN) ];
            if(addr && (addr->sin_family==AF_INET || addr->sin_family==AF_INET6)) {
                NSString *name = [NSString stringWithUTF8String:interface->ifa_name];
                NSString *type;
                if(addr->sin_family == AF_INET) {
                    if(inet_ntop(AF_INET, &addr->sin_addr, addrBuf, INET_ADDRSTRLEN)) {
                        type = IP_ADDR_IPv4;
                    }
                } else {
                    const struct sockaddr_in6 *addr6 = (const struct sockaddr_in6*)interface->ifa_addr;
                    if(inet_ntop(AF_INET6, &addr6->sin6_addr, addrBuf, INET6_ADDRSTRLEN)) {
                        type = IP_ADDR_IPv6;
                    }
                }
                if(type) {
                    NSString *key = [NSString stringWithFormat:@"%@/%@", name, type];
                    addresses[key] = [NSString stringWithUTF8String:addrBuf];
                }
            }
        }
        // Free memory
        freeifaddrs(interfaces);
    }
    return [addresses count] ? addresses : nil;
}

上面这个方法是获取IP地址

dic[@"ip"] = [self getIPAddress:YES]; // 调用方法获取IP

然后接口返回签名和调起微信需要的参数

//调起微信支付
PayReq* req             = [[PayReq alloc] init];
req.openID              = [dataDic objectForKey:@"appid"];
req.partnerId           = [dataDic objectForKey:@"mch_id"];
req.prepayId            = [dataDic objectForKey:@"prepay_id"];
req.nonceStr            = [dataDic objectForKey:@"nonce_str"];
req.timeStamp           = [[dataDic objectForKey:@"timestamp"] intValue];
req.package             = @"Sign=WXPay";

拿到参数之后，把链接拼接然后再进行第二次签名也就是加密接口

NSString *origin = [NSString stringWithFormat:@"appid=%@&noncestr=%@&package=%@&partnerid=%@&prepayid=%@&timestamp=%d",[dataDic objectForKey:@"appid"],[dataDic objectForKey:@"nonce_str"],@"Sign=WXPay",[dataDic objectForKey:@"mch_id"],[dataDic objectForKey:@"prepay_id"],[[dataDic objectForKey:@"timestamp"] intValue]];
NSString *stringSignTemp = [NSString stringWithFormat:@"%@&key=%@",origin,[dataDic objectForKey:@"key"]];

最后复制sign值，调起微信搞定。

req.sign                = [self md5:stringSignTemp]; // 加密接口用的方法 在下面
[WXApi sendReq:req];

- (NSString *) md5:(NSString *) input {
    const char *cStr = [input UTF8String];
    unsigned char digest[CC_MD5_DIGEST_LENGTH];
    CC_MD5( cStr, strlen(cStr), digest ); // This is the md5 call
    
    NSMutableString *output = [NSMutableString stringWithCapacity:CC_MD5_DIGEST_LENGTH * 2];
    
    for(int i = 0; i < CC_MD5_DIGEST_LENGTH; i++)
        [output appendFormat:@"%02x", digest[i]];
    
    return output;
}

• 基本上就这么多吧。