javascript – 未捕获的SyntaxError：await仅在async函数中有效(虽然它在异步函数中…)

2019年7月28日 235次阅读

所以我不知道是什么导致了这个问题,我花了至少30分钟搜索谷歌并尝试不同的东西没有解决方案.我已经定义了一个异步函数,我试图在它内部使用await但它给了我

Error: Uncaught SyntaxError: await is only valid in async function

这是代码：

function sleep(ms) {
  return new Promise(resolve => setTimeout(resolve, ms));
}
async function SolveRecaptchaV2(APIKey, googleKey, pageUrl, proxy, proxyType){
            var requestUrl = "https://2captcha.com/in.php?key=" + APIKey + "&method=userrecaptcha&googlekey=" + googleKey + "&pageurl=" + pageUrl + "&proxy=" + proxy + "&proxytype=";

            switch (proxyType) {
                case 'HTTP':
                requestUrl = requestUrl + "HTTP";
                break;

                case 'HTTPS':
                requestUrl = requestUrl + "HTTPS";
                break;

                case 'SOCKS4':
                requestUrl = requestUrl + "SOCKS4";
                break;

                case 'SOCKS5':
                requestUrl = requestUrl + "SOCKS5";
                break;
            }   
            $.ajax({url: requestUrl, success: function(result){
                if(result.length < 3){
                    return false;
                }else{
                    if(result.substring(0, 3) == "OK|"){
                        var captchaID = result.substring(3);

                        for(var i=0; i<24; i++){
                            var ansUrl = "https://2captcha.com/res.php?key=" + APIKey + "&action=get&id=" + captchaID;  

                            $.ajax({url: ansUrl, success: function(ansresult){
                                    console.log(ansresult);
                                    if(ansresult.length < 3){
                                        return ansresult;
                                    }else{
                                        if(ansresult.substring(0, 3) == "OK|"){
                                            return ansresult;
                                        }else if (ansresult != "CAPCHA_NOT_READY"){
                                            return ansresult;
                                        }
                                    }
                                }
                            });
                            await sleep(1000);
                        }

                    }else{
                        return ansresult;   
                    }
                }
            },
            fail: function(){
                return "";
                }
            });

        }

编辑::现在,当我使$.ajax回调函数成为异步函数时,$.ajax调用都没有工作,并且我在其中制作的任何console.log都没有在控制台中显示…我没有得到任何错误虽然

最佳答案 所以这里的主要问题是,你在$.ajax函数的成功函数中使用等待(这是不可能的,不能使这个函数同步,但现在因为你的代码混合了回调/异步,你不是能够解决SolveRecaptchaV2的原始Promise.你将异步与旧的回调混合.)你的代码本质上是这样做的：

SolveRecaptchaV2 => Ajax Request => Ajax Request Done, Firing callback
                         V                         V
                     Returning         Returning (But nothing cares about this return)

如果您正在使用异步功能,请尝试尽可能多地使用异步. $.ajax将返回一个promise,所以我们可以等待,并保持我们的函数完全异步：

function sleep(ms) {
  return new Promise(resolve => setTimeout(resolve, ms));
}

async function SolveRecaptchaV2(APIKey, googleKey, pageUrl, proxy, proxyType){
    var requestUrl = "https://2captcha.com/in.php?key=" + APIKey + "&method=userrecaptcha&googlekey=" + googleKey + "&pageurl=" + pageUrl + "&proxy=" + proxy + "&proxytype=";

    switch (proxyType) {
        case 'HTTP':
        requestUrl = requestUrl + "HTTP";
        break;

        case 'HTTPS':
        requestUrl = requestUrl + "HTTPS";
        break;

        case 'SOCKS4':
        requestUrl = requestUrl + "SOCKS4";
        break;

        case 'SOCKS5':
        requestUrl = requestUrl + "SOCKS5";
        break;
    }   
    try {
        await result = await $.ajax({url: requestUrl});

        if(result.length < 3) {
            return false;
        } else {
            if(result.substring(0, 3) == "OK|") {
                var captchaID = result.substring(3);

                for(var i=0; i<24; i++){
                    var ansUrl = "https://2captcha.com/res.php?key=" + APIKey + "&action=get&id=" + captchaID;  

                    var ansResult = await $.ajax({url: ansUrl});
                    console.log(ansResult);
                    if(ansResult.length < 3) {
                        return ansResult;
                    } else {
                        if(ansresult.substring(0, 3) == "OK|") {
                            return ansResult;
                        } else if (ansResult != "CAPCHA_NOT_READY") {
                            return ansResult;
                        }
                    }
                    await sleep(1000);
                }
            } else {
                // ansResult is not defined here, not sure what you want to return here (May want to return false, or an empty string):
                return ansResult;   
            }
        }
    } catch (err) {
        //On ajax failure, return empy string. (May want to return false here, to fall inline with your "if (result.length < 3)" statement above.)
        return "";
    }
}

现在我们的链看起来像这样：

SolveRecaptchaV2 => Ajax Request
                     => Ajax Request Done
                       => Get Answer URL
                         => Sleep
                           => Get Answer URL
                             => Sleep (...loop)
                               => Resolve promise of SolveRecaptchaV2.
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