我在使用异步瀑布时遇到问题，我发现在调用第二个回调（cbNumPages）后，第一个参数＆＃34; pages＆＃34;是下一个函数的实际回调，而不是最后一个参数＆＃34; cbGetFiles＆＃34;它应该是（据我所知async瀑布说最后一个参数应该总是回调，在这种情况下显然不是）。
代码如下：
async.waterfall
([
function(cbNumPages)
{
request({
url: 'any-url',
qs: {},
method: 'GET',
headers: {
'Authorization' : 'any-auth'
}
}, (err, response, body) => {
if (!err && response.statusCode == 200)
{
var $ = cheerio.load(body);
var pagesList = $('ol.aui-nav').children();
if(pagesList.length<1)
{
var numPages = 1;
} else {
var numPages = pagesList.length-2;
}
console.log(numPages);
var pages = new Array(numPages),
total = numPages*20,
iterator = 0;
async.eachSeries(pages, function(page, cb)
{
if(page>1)
{
pages[iterator] = iterator;
}else {
pages[iterator] = iterator*20;
}
iterator++;
cb();
}, function(err){
if(err) cbNumPages(err);
cbNumPages(null, pages);
});
} else {
cbNumPages(err);
}
})
},
function(pages, cbGetFiles)
{
var files = [];
var limitDate = moment().tz('Europe/Madrid').subtract(330,'days').format();
async.eachSeries(pages, function(page, cb)
{
request({
url: 'any-url'+page,
qs: {},
method: 'GET',
headers: {
'Authorization' : 'any-auth'
}
}, (err, response, body) => {
if(!err && response.statusCode == 200)
{
var $ = cheerio.load(body);
var rows = $('tr[id^=\'attachment-\']');
async.eachLimit(rows, 1, function(row, cb)
{
var id = row.attribs['id'];
var file = row.attribs['data-attachment-filename'];
var author = $(row).children('.creator').text().trim();
var created = $(row).children('.created-date').text().trim();
created = moment.tz(created, 'MMM D, YYYY', 'Europe/Madrid').format();
var urlFile = 'simple-file' + $(row).children('.filename-column').children('.filename').attr('href');
var extension = row.attribs['data-attachment-filename'].split('.');
extension = extension[extension.length-1];
if(created<limitDate && validExtensions.indexOf(extension)>-1)
{
var f = '{ "id": "' + id + '",';
f += ' "file": "' + file + '",';
f += ' "url": "' + urlFile + '",';
f += ' "author": "' + author + '",';
f += ' "modified": "' + created + '" }';
files.push(JSON.parse(f));
}
cb();
}, (err) => {
if(err) cbGetFiles(err);
});
cb();
} else {
cb(err);
}
});
}, function(err){
if(err){
cbGetFiles(err);
} else {
cbGetFiles(null, files);
}
});
},
function(files, cbGetAutors)
{
var filesFinal = {};
for(var f in files)
{
if(!filesFinal[files[f].author])
{
var ff = {};
for(var i in files)
{
if(files[i].author === files[f].author)
{
ff[files[i].file] = files[i].url;
}
}
filesFinal[files[f].author] = ff;
}
}
cbGetAutors(null, JSON.parse(JSON.stringify(filesFinal)));
},
function(filesFinal, cbSendEmail)
{
var authors = Object.keys(filesFinal);
async.eachSeries(authors, function(author, cb)
{
var name = author.split(' ');
var email = 'simple-mail@gmail.com';
var msg = '<p>Hi ' + author + ',</p><p>how is it going:</p><p>';
for(var a in Object.keys(filesFinal[author]))
{
msg += '<p style="margin-left:20px"> '+ICON_DOC+' <a href="';
msg += filesFinal[author][Object.keys(filesFinal[author])[a]]+'">'+Object.keys(filesFinal[author])[a]+'</a></p>';
}
msg += '</p></p><p><b>NOTE: This is a no-reply address.</b></p><p>Have a nice day! '+ICON_MONKEY+'</p>';
var message = {
text: msg,
from: 'test@mail.com',
to: email,
bcc: '',
subject: 'Sample subject',
attachment: [{data: msg, alternative: true}]
};
serverEmail.send(message, function(err, message)
{
if(err)
{
cb(err);
} else {
console.log(message);
cb();
}
});
}, function(err){
if(err) cbSendEmail(err);
cbSendEmail();
});
}
], (err) => {
if(err) console.log(err);
});
我想知道是否有办法控制这个问题，或者至少是否有其他选项可以解决这个问题。
感谢。
答案 0 :(得分：2)
使用异步瀑布的更好（整洁）方式。
确保在任何回调函数之前使用return。我在代码中添加了它们。
另外，如果要嵌套eachSeries，最好为回调函数指定一个与父回调函数不同的名称。
我已将子async.series的'cb'更改为'inner_cb'
更新代码：
async.waterfall
([
funcOne,
funcTwo,
funcThree,
funcFour
], (err) => {
if(err) console.log(err);
});
funciton funcOne(cbNumPages) {
request({
url: 'any-url',
qs: {},
method: 'GET',
headers: {
'Authorization' : 'any-auth'
}
}, (err, response, body) => {
if (!err && response.statusCode == 200)
{
var $ = cheerio.load(body);
var pagesList = $('ol.aui-nav').children();
if(pagesList.length<1)
{
var numPages = 1;
} else {
var numPages = pagesList.length-2;
}
console.log(numPages);
var pages = new Array(numPages),
total = numPages*20,
iterator = 0;
async.eachSeries(pages, function(page, cb)
{
if(page>1)
{
pages[iterator] = iterator;
}else {
pages[iterator] = iterator*20;
}
iterator++;
return cb();
}, function(err){
if(err) return cbNumPages(err);
return cbNumPages(null, pages);
});
} else {
return cbNumPages(err);
}
})
}
function funcTwo(pages, cbGetFiles) {
var files = [];
var limitDate = moment().tz('Europe/Madrid').subtract(330,'days').format();
async.eachSeries(pages, function(page, cb)
{
request({
url: 'any-url'+page,
qs: {},
method: 'GET',
headers: {
'Authorization' : 'any-auth'
}
}, (err, response, body) => {
if(!err && response.statusCode == 200)
{
var $ = cheerio.load(body);
var rows = $('tr[id^=\'attachment-\']');
async.eachLimit(rows, 1, function(row, inner_cb)
{
var id = row.attribs['id'];
var file = row.attribs['data-attachment-filename'];
var author = $(row).children('.creator').text().trim();
var created = $(row).children('.created-date').text().trim();
created = moment.tz(created, 'MMM D, YYYY', 'Europe/Madrid').format();
var urlFile = 'simple-file' + $(row).children('.filename-column').children('.filename').attr('href');
var extension = row.attribs['data-attachment-filename'].split('.');
extension = extension[extension.length-1];
if(created<limitDate && validExtensions.indexOf(extension)>-1)
{
var f = '{ "id": "' + id + '",';
f += ' "file": "' + file + '",';
f += ' "url": "' + urlFile + '",';
f += ' "author": "' + author + '",';
f += ' "modified": "' + created + '" }';
files.push(JSON.parse(f));
}
return inner_cb();
}, (err) => {
if(err) return cbGetFiles(err);
});
return cb();
} else {
return cb(err);
}
});
}, function(err){
if(err){
return cbGetFiles(err);
} else {
return cbGetFiles(null, files);
}
});
}
function funcThree(files, cbGetAutors) {
var filesFinal = {};
for(var f in files)
{
if(!filesFinal[files[f].author])
{
var ff = {};
for(var i in files)
{
if(files[i].author === files[f].author)
{
ff[files[i].file] = files[i].url;
}
}
filesFinal[files[f].author] = ff;
}
}
return cbGetAutors(null, JSON.parse(JSON.stringify(filesFinal)));
}
function funcFour(filesFinal, cbSendEmail) {
var authors = Object.keys(filesFinal);
async.eachSeries(authors, function(author, cb)
{
var name = author.split(' ');
var email = 'simple-mail@gmail.com';
var msg = '<p>Hi ' + author + ',</p><p>how is it going:</p><p>';
for(var a in Object.keys(filesFinal[author]))
{
msg += '<p style="margin-left:20px"> '+ICON_DOC+' <a href="';
msg += filesFinal[author][Object.keys(filesFinal[author])[a]]+'">'+Object.keys(filesFinal[author])[a]+'</a></p>';
}
msg += '</p></p><p><b>NOTE: This is a no-reply address.</b></p><p>Have a nice day! '+ICON_MONKEY+'</p>';
var message = {
text: msg,
from: 'test@mail.com',
to: email,
bcc: '',
subject: 'Sample subject',
attachment: [{data: msg, alternative: true}]
};
serverEmail.send(message, function(err, message)
{
if(err)
{
return cb(err);
} else {
console.log(message);
return cb();
}
});
}, function(err){
if(err) return cbSendEmail(err);
return cbSendEmail();
});
}
答案 1 :(得分：0)
正如@YSK在评论中所说的那样，我从response.statusCode中获取了一个401，因此它被误导到cbSendEmail（错误），并且错误地冒犯了null。在瀑布的第一个参数中使用下一个方法，而不是第二个参数。