我有一个承诺,即收集文件的元数据,然后使用收集的元数据解析它。以下是我试图获得结果的方法:
getMetadata: function(text, url){
return this.getpageno(url).then(function(pagecount){
return new Promise(function(accept, reject){
var result = []
var dataMatch = rx.exec(text)
var produktDaten = dataMatch[1].split("&&&").filter(Boolean);
var dokuArr = dataMatch[2].split("&&&").filter(Boolean);
console.log('the produktdaten are ' + produktDaten)
for (var i=0; i<produktDaten.length; i+=4){
var entry = {}
for(var j=0; j<dokuArr.length; j+=3){
var seite = dokuArr[j+2];
// make sure seite is a digit
if (!(/^\d+$/.test(seite))){
console.log(seite + ' was not a valid page number')
throw err
}
if (/(A|a)lle?/i.test(nummer)){
entry.kks.pages[beschreibung] = seite;
// })
}
else if (nummer === kksNummer) {
entry.kks.pages[beschreibung] = seite;
}
}
entry.hersteller = produktDaten[i+1]
entry.typ = produktDaten[i+2]
entry.artikelNummer = produktDaten[i+3]
result.push(entry)
}
if (result.length>0){
return accept(result)
}
return reject()
})
})
},
getpageno: function(url){
var self=this
var pdf = pdfjs.getDocument(url);
return pdf.then(function(pdf){
var maxPages = pdf.pdfInfo.numPages;
var countPromises = []; // collecting all page promises
for (var j = 1; j <= maxPages; j++) {
try {
var page = pdf.getPage(j);
var txt = "";
countPromises.push(page.then(function(page) { // add page promise
var textContent = page.getTextContent();
return textContent.then(function(text){ // return content promise
return text.items.map(function (s) { return s.str; }).join('&&&'); // value page text
});
}));
}
catch(e){
console.log(e)
}
}
// Wait for all pages and join text
return Promise.all(countPromises).then(function (texts) {
// since doumentation pages do not add the final '&&&', must add one manually (only after rx has been found)
var fulltext = texts.reduce(function(full, text){
if (rx.test(full)){
var next = '&&&'+text
return full+=next
}
return full+=text
}, '')
return [fulltext, texts]
});
}).then(function(textarr){
var fulltext = textarr[0]
self.fulltext = fulltext;
var texts = textarr[1]
try {
var partialmatch = rx.exec(fulltext)[0]
var count = texts.reduce(function(pageno, text){
var tomatch = text.replace(/.*Typ&&&/, '')
if (tomatch.length>0 && partialmatch.indexOf(tomatch) > -1){
pageno++
}
return pageno;
}, 0)
}
catch(e){
console.log(e)
}
return count;
})
}
编辑该条目以显示我现在正在返回gepageno函数的值。
我期待的数据已被记录,但由于accept()
而无法使用。任何人都能说出可能出现的问题吗?
答案 0 :(得分:1)
我试图模拟并解决你的承诺。我发布了伪代码。
承诺流程
var testFunction = ((result) => {
return new Promise(function (resolve, reject) {
var err = null;
if (!!err) {
reject(err);
} else {
console.log("2. testFunction resolved");
resolve("Final response");
}
});
});
var getpageno = ((url) => {
return new Promise((resolve, reject) => {
var err = null;
if (!!err) {
reject(err);
} else {
console.log("1. getpageno resolved");
resolve(45);
}
});
});
var getMetadata = ((text, url) => {
console.log("0. getmetadata resolved");
var self = this;
getpageno(url)
.then((pageCount) => {
console.log("> pageCount :", pageCount);
return testFunction(pageCount);
})
.then((data) => {
console.log(">", data);
});
});
getMetadata("hell", "https://www.google.com");
输出
0. getmetadata resolved
1. getpageno resolved
> pageCount : 452. testFunction resolved
> Final response
答案 1 :(得分:0)
您需要在第三行返回承诺
return self.getpageno(url).then
访问其最终履行价值。