我遇到了问题。我有多个回调函数。
循环中函数内的函数
我想首先完全执行第一个函数。然后我想进一步。
Currenlty没有功能正常工作：
function recurring_end() {
var diffbot = new Diffbot('ddddd');
var sql= "SELECT `bookmarks`.`id`,`bookmarks`.`bookmark_url` as url FROM bookmarks LIMIT 0, 10";
connection.query(sql, function(err,bookmarks) {
console.log(JSON.parse(JSON.stringify(bookmarks)));
for(var i = 0; i< bookmarks.length; i++){
(function(i) {
bookmark_id = bookmarks[i].id;
bookmark_url = bookmarks[i].url;
parseArticle(i,bookmark_id,bookmark_url,function(err,result){
bookamrk_title= result.bookmark_title;
bookmark_body= result.body;
bookmark_file_name= result.file_name;
preview_image = result.preview_image;
local_image_name = result.local_image_name;
mainPreviewImage = result.mainPreviewImage;
viewImage=result.viewImage;
var mediaExist =result.mediaExist;
if(mediaExist == 1) {
console.log("Entered in Media Exist");
download(preview_image, "images/" + local_image_name, function() {
console.log("Entered in download");
fs.exists("images/" + local_image_name, function(exists) {
console.log("Before Sending " +mainPreviewImage);
console.log("Before Sending Local " +local_image_name);
ImageMagic(local_image_name,mainPreviewImage,223,147,function(err,result) {
if(result != 0){
mainPreviewImage= result;
console.log("Image Magic Done" +mainPreviewImage);
AmazonUpload(mainPreviewImage,function(err,result) {
console.log("Amazon error "+err);
if(result != 0){
mainPreviewImage = result;
console.log("First Image Uploading is Sucessfully");
/* Now Lets Pass View Image FROM Graphic Magic */
ImageMagic(mainPreviewImage,viewImage,152,100,function(err,result) {
if(result != 0){
viewImage= result;
/* Upload New View File to Amazon */
AmazonUpload(viewImage,function(err,result) {
if(result != 0){
viewImage = result;
console.log("Second Image Upload to Amazon");
/*Finally here we need to write update logic here check it out */
console.log("Serious id is "+i);
console.log("Book Mark id " +bookmark_id);
console.log("bookamrk_title" +bookamrk_title);
console.log("preview_image"+mainPreviewImage);
console.log("viewImage"+viewImage);
console.log("End " +ddd);
}else {
/* need to write update Query here */
var viewImage="thumbnail_default_bookmark1.png";
}
});
}else{
/* need to write update Query here */
var viewImage="thumbnail_default_bookmark1.png";
}
});
}else {
/* need to writeUpdate Query Here */
var mainPreviewImage= 'default_bookmark.png';
var viewImage="thumbnail_default_bookmark1.png";
}
});
}else{
/* need to write Update Query here */
var mainPreviewImage= 'default_bookmark.png';
var viewImage="thumbnail_default_bookmark1.png";
}
});
});
});/* download function closed */
}
});
})(i);
}
console.log("Every Thing is done ");
});
}
function AmazonUpload(uploadImage,callback) {
knox.putFile('images/'+uploadImage,'BookmarkPreviewImages/'+uploadImage, {"Content-Type": "image/jpeg",'x-amz-acl': 'public-read'}, function (err, result) {
if(!err){
if(result.statusCode==200){
callback(err,uploadImage);
}else{
callback(err,0);
}
}else{
callback(err,0);
}
});
}
function download(uri, filename, callback) {
request.head(uri, function(err, res, body) {
//request(uri).pipe(fs.createWriteStream(filename),{end:true}).on('close', callback);
var r = request(uri);
r.pause()
r.on('response', function (resp) {
if(resp.statusCode === 200){
r.pipe(fs.createWriteStream(filename),{end:true}).on('close', callback); //pipe to where you want it to go
r.resume()
}
});
});
};
function ImageMagic(local_image_name,display_image,width,height,callback){
console.log("local_image_name is"+local_image_name);
gm('images/'+local_image_name).resize(width, height, '^').gravity('Center').crop(width, height).write('images/'+display_image, function (err) {
if(!err){
console.log("Sucessfully Image converted is "+display_image);
console.log("Sucessfully image which is converted "+ local_image_name);
callback(null,display_image);
}else{
console.log("Graphic Magic Error "+err);
callback(err,0);
}
});
}
function parseArticle(i,bookmark_id,bookmark_url,callback) {
diffbot.article({uri: bookmark_url}, function(err, response) {
var callBackString= {};
console.log("Diffbot Parsing URL with id " +bookmark_id+"and loop id is"+i);
var bookmark_title = response.title;
var body = response.html;
var timestamp = new Date().getTime().toString();
var file_name = common_function.generateRandomString() + timestamp + '.txt';
var timestamp0 = new Date().getTime().toString();
var local_image_name = common_function.generateRandomString() + timestamp0 + i + '.jpg';
var preview_image = response.media[0]['link'];
if(response.media[0].primary=='true'){
mainPreviewImage = "thumb_" + local_image_name;
viewImage = "thumbnail_" + local_image_name;
mediaExist=1;
}else{
mainPreviewImage="default_bookmark.png";
viewImage="thumbnail_default_bookmark1.png";
mediaExist=0;
}
callBackString .bookmark_title=bookmark_title;
callBackString.body = body;
callBackString.file_name = file_name;
callBackString.preview_image = preview_image;
callBackString.local_image_name = local_image_name;
callBackString.mainPreviewImage = mainPreviewImage;
callBackString.viewImage=viewImage;
callBackString.mediaExist =mediaExist;
callback(null,callBackString);
});
};
我理解代码太长了。我想得到一个想法，我想先完全执行i=0，然后我想继续前进。
我们如何在Nodejs中做任何想法。任何帮助都将得到满足 感谢
答案 0 :(得分：2)
尝试用这样的递归代码替换循环..
function recurring_end() {
var diffbot = new Diffbot('ddddd');
var sql= "SELECT `bookmarks`.`id`,`bookmarks`.`bookmark_url` as url FROM bookmarks LIMIT 0, 10";
connection.query(sql, function(err,bookmarks) {
console.log(JSON.parse(JSON.stringify(bookmarks)));
var i = 0;
var callbackForParseArticle = function(err,result){
bookamrk_title= result.bookmark_title;
bookmark_body= result.body;
bookmark_file_name= result.file_name;
preview_image = result.preview_image;
local_image_name = result.local_image_name;
mainPreviewImage = result.mainPreviewImage;
viewImage=result.viewImage;
var mediaExist =result.mediaExist;
if(mediaExist == 1) {
console.log("Entered in Media Exist");
download(preview_image, "images/" + local_image_name, function() {
console.log("Entered in download");
fs.exists("images/" + local_image_name, function(exists) {
console.log("Before Sending " +mainPreviewImage);
console.log("Before Sending Local " +local_image_name);
ImageMagic(local_image_name,mainPreviewImage,223,147,function(err,result) {
if(result != 0){
mainPreviewImage= result;
console.log("Image Magic Done" +mainPreviewImage);
AmazonUpload(mainPreviewImage,function(err,result) {
console.log("Amazon error "+err);
if(result != 0){
mainPreviewImage = result;
console.log("First Image Uploading is Sucessfully");
/* Now Lets Pass View Image FROM Graphic Magic */
ImageMagic(mainPreviewImage,viewImage,152,100,function(err,result) {
if(result != 0){
viewImage= result;
/* Upload New View File to Amazon */
AmazonUpload(viewImage,function(err,result) {
if(result != 0){
viewImage = result;
console.log("Second Image Upload to Amazon");
/*Finally here we need to write update logic here check it out */
console.log("Serious id is "+i);
console.log("Book Mark id " +bookmark_id);
console.log("bookamrk_title" +bookamrk_title);
console.log("preview_image"+mainPreviewImage);
console.log("viewImage"+viewImage);
console.log("End " +ddd);
}else {
/* need to write update Query here */
var viewImage="thumbnail_default_bookmark1.png";
}
//additional lines to the end of the function
i++;
if (i<bookmarks.length){
bookmark_id = bookmarks[i].id;
bookmark_url = bookmarks[i].url;
parseArticle(i,bookmark_id,bookmark_url,callbackForParseArticle);
} else {
console.log("Every Thing is done ");
}
});
}else{
/* need to write update Query here */
var viewImage="thumbnail_default_bookmark1.png";
}
});
}else {
/* need to writeUpdate Query Here */
var mainPreviewImage= 'default_bookmark.png';
var viewImage="thumbnail_default_bookmark1.png";
}
});
}else{
/* need to write Update Query here */
var mainPreviewImage= 'default_bookmark.png';
var viewImage="thumbnail_default_bookmark1.png";
}
});
});
});/* download function closed */
}
};
if (bookmarks.length > 0){
parseArticle(i,bookmarks[i].id,bookmarks[i].url,callbackForParseArticle);
}
});
}
function AmazonUpload(uploadImage,callback) {
knox.putFile('images/'+uploadImage,'BookmarkPreviewImages/'+uploadImage, {"Content-Type": "image/jpeg",'x-amz-acl': 'public-read'}, function (err, result) {
if(!err){
if(result.statusCode==200){
callback(err,uploadImage);
}else{
callback(err,0);
}
}else{
callback(err,0);
}
});
}
function download(uri, filename, callback) {
request.head(uri, function(err, res, body) {
//request(uri).pipe(fs.createWriteStream(filename),{end:true}).on('close', callback);
var r = request(uri);
r.pause()
r.on('response', function (resp) {
if(resp.statusCode === 200){
r.pipe(fs.createWriteStream(filename),{end:true}).on('close', callback); //pipe to where you want it to go
r.resume()
}
});
});
};
function ImageMagic(local_image_name,display_image,width,height,callback){
console.log("local_image_name is"+local_image_name);
gm('images/'+local_image_name).resize(width, height, '^').gravity('Center').crop(width, height).write('images/'+display_image, function (err) {
if(!err){
console.log("Sucessfully Image converted is "+display_image);
console.log("Sucessfully image which is converted "+ local_image_name);
callback(null,display_image);
}else{
console.log("Graphic Magic Error "+err);
callback(err,0);
}
});
}
function parseArticle(i,bookmark_id,bookmark_url,callback) {
diffbot.article({uri: bookmark_url}, function(err, response) {
var callBackString= {};
console.log("Diffbot Parsing URL with id " +bookmark_id+"and loop id is"+i);
var bookmark_title = response.title;
var body = response.html;
var timestamp = new Date().getTime().toString();
var file_name = common_function.generateRandomString() + timestamp + '.txt';
var timestamp0 = new Date().getTime().toString();
var local_image_name = common_function.generateRandomString() + timestamp0 + i + '.jpg';
var preview_image = response.media[0]['link'];
if(response.media[0].primary=='true'){
mainPreviewImage = "thumb_" + local_image_name;
viewImage = "thumbnail_" + local_image_name;
mediaExist=1;
}else{
mainPreviewImage="default_bookmark.png";
viewImage="thumbnail_default_bookmark1.png";
mediaExist=0;
}
callBackString .bookmark_title=bookmark_title;
callBackString.body = body;
callBackString.file_name = file_name;
callBackString.preview_image = preview_image;
callBackString.local_image_name = local_image_name;
callBackString.mainPreviewImage = mainPreviewImage;
callBackString.viewImage=viewImage;
callBackString.mediaExist =mediaExist;
callback(null,callBackString);
});
};
答案 1 :(得分：1)
使用async.js管理您的代码流
如果你有多个函数，func_1，func_2，func_3，需要按顺序运行，代码是
var async = require('async');
var functionList = [func_1, func_2, func_3];
async.series(functionList, function(err, result){
// results of func_1, func_2 and func_3
});