如何使用JavaScript通过GET请求之前发送

Question

目前我正在Chrome扩展我想特别是电子邮件（即MESSAGE_ID = 1543c2a6347d984c）附件数据获取Gmail附件。我得到了email message_id也获得了附件文件名（即abc.zip），但是如何获得该附件并使用Ajax发送回我的服务器。

function getAttachments(userId, message, callback) { 
    var parts = message.payload.parts; 
    for (var i = 0; i < parts.length; i++) { 
    var part = parts[i]; 
    if (part.filename && part.filename.length > 0) { 
     var attachId = part.body.attachmentId; 
     var request = gapi.client.gmail.users.messages.attachments.get({ 
     'id': attachId, 
     'messageId': message.id, 
     'userId': userId 
     }); 
     request.execute(function(attachment) { 
     callback(part.filename, part.mimeType, attachment); 
     }); 
    } 
    } 
} 

调用

var userId="xyz@gmail.com" 
    var message_id="1543c2a6347d984d"; 

    getAttachments(userId,message_id,function callback(filename,minetype,attachment){ 

console.log('File Name is '+filename); 
console.log('MimeType is '+minetype); 
}); 

错误： main.js：15遗漏的类型错误：无法读取的未定义的属性 '零件'（功能getAttachments 2号线）

Answer 1

你MESSAGE_ID是字符串，然后你调用getAttachments方法并将其作为第二个参数传递，在getAttachments中，你调用message.payload.parts，这意味着你想得到一个属性​​，当然是undefined。

拿着赃物Users.messages.get和Users.messages.attachments.get，您需要先收到消息，然后从中获取附件。

function getAttachments(userId, message, callback) { 
    var parts = message.payload.parts; 
    for (var i = 0; i < parts.length; i++) { 
    var part = parts[i]; 
    if (part.filename && part.filename.length > 0) { 
     var attachId = part.body.attachmentId; 
     var request = gapi.client.gmail.users.messages.attachments.get({ 
     'id': attachId, 
     'messageId': message.id, 
     'userId': userId 
     }); 
     request.execute(function(attachment) { 
     callback(part.filename, part.mimeType, attachment); 
     }); 
    } 
    } 
} 

function getMessage(userId, messageId, callback) { 
    var request = gapi.client.gmail.users.messages.get({ 
    'userId': userId, 
    'id': messageId 
    }); 
    request.execute(function(message) { 
     callback(userId, message); 
    }); 
} 

var userId="xyz@gmail.com" 
var message_id="1543c2a6347d984d"; 

getMessage(userId, message_id, function(userId, message) { 
    getAttachments(userId, message, function(filename,minetype,attachment) { 
     console.log('File Name is '+filename); 
     console.log('MimeType is '+minetype); 
    }); 
});