将 Blob 数据转换为 JavaScript 或节点中的原始缓冲区
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Convert Blob data to Raw buffer in javascript or node
提问by Kamaldeep Singh
I am using a plugin jsPDFwhich generates PDF and saves it to local file system. Now in jsPDF.js, there is some piece of code which generates pdf data in blob format as:-
我正在使用插件jsPDF生成 PDF 并将其保存到本地文件系统。现在在 jsPDF.js 中，有一些代码可以生成 blob 格式的 pdf 数据，如下所示：-
var blob = new Blob([array], {type: "application/pdf"});
and further saves the blob data to local file system. Now instead of saving I need to print the PDF using plugin node-printer.
并进一步将 blob 数据保存到本地文件系统。现在我需要使用插件node-printer打印 PDF 而不是保存。
Here is some sample code to do so
这是一些示例代码
var fs = require('fs'),
var dataToPrinter;
fs.readFile('/home/ubuntu/test.pdf', function(err, data){
dataToPrinter = data;
}
var printer = require("../lib");
printer.printDirect({
data: dataToPrinter,
printer:'Deskjet_3540',
type: 'PDF',
success: function(id) {
console.log('printed with id ' + id);
},
error: function(err) {
console.error('error on printing: ' + err);
}
})
The fs.readFile()reads the PDF file and generates data in raw buffer format.
在fs.readFile()读取PDF文件，并生成原始缓冲区格式的数据。
Now what I want is to convert the 'Blob' data into 'raw buffer' so that I can print the PDF.
现在我想要的是将“Blob”数据转换为“原始缓冲区”，以便我可以打印 PDF。
回答by Kamaldeep Singh
var blob = new Blob([array], {type: "application/pdf"});
var arrayBuffer, uint8Array;
var fileReader = new FileReader();
fileReader.onload = function() {
arrayBuffer = this.result;
uint8Array = new Uint8Array(arrayBuffer);
var printer = require("./js/controller/lib");
printer.printDirect({
data: uint8Array,
printer:'Deskjet_3540',
type: 'PDF',
success: function(id) {
console.log('printed with id ' + id);
},
error: function(err) {
console.error('error on printing: ' + err);
}
})
};
fileReader.readAsArrayBuffer(blob);
This is the final code which worked for me. The printer accepts uint8Array encoding format.
这是对我有用的最终代码。打印机接受 uint8Array 编码格式。
回答by Alexandr Lazarev
Try:
尝试：
var blob = new Blob([array], {type: "application/pdf"});
var buffer = new Buffer(blob, "binary");
