I have app on Heroku and I want to capture webpage and save as image or base64. Problem is: I have node.js script in that app and I want to use phantomjs, but phantom is not compatible with node.
So, I need to capture webpage and save output (image or base64 string) to variable so my primary (node) app can use that values.
I tried this but I can't figure how to use that: https://www.npmjs.com/package/phantom
This is what I have so far: (source)
app.get('/capture', function(request, response) {
var phantom = require('phantom');
phantom.create().then(function(ph) {
ph.createPage().then(function(page) {
page.open('https://stackoverflow.com/').then(function(status) {
console.log(status);
page.property('content').then(function(content) {
var base64 = page.renderBase64('PNG');
console.log(base64);
page.close();
ph.exit();
});
});
});
});
});
What I need on my heroku server (beside already installed node), what I need to install in node.js, how to use all that?
Thanks.
So: send request to capture page -> make image -> pass output to JS variable
Related
I am using a node sever to send a table from a sqlite db to the browser. This table contains filename and path of a pdf file that I want to render on the browser. Until now I was using hard coded paths for the the pdf file and rendering. But now i have setup a get route and a controller in node such that whenever '/content' is hit in browser , the server queries the database and and sends the data to the client. To the send the data I am using
res.render('content/index',{data:queryData});
Now, how do I access this data using client side javascript so that I can pass the path of the pdf file to the function that renders the pdf? I have done research and the nearest answer I got was using XMLHttpRequest. I tried this method
var xhr = new XMLHttpRequest();
const path = "http://localhost:3000/content";
xhr.onreadystatechange = function () {
if (xhr.readyState == 4 && xhr.status == 200)
{
var myResponseText = xhr.responseText;
console.log(myResponseText);
}
};
xhr.open('get', path, true);
xhr.send();
When I do this I get the entire html code for the view. Not the data I expected. How do I solve this issue. I have done some more reading while writing this post and I suppose. I have set a header somewhere? But the documentation says
app.render(view, [locals], callback)
which means res.render can take local variables, shouldn't be setting the headers?
You should return json instead of render template:
app.get('content/index', (req, res) => {
res.json({data: queryData});
});
I am using pdf.js
PDF.js needs the PDF file, e.g.:
pdfjsLib.getDocument('helloworld.pdf')
I'm assuming your queryData goes something like this:
{ filename: 'file.pdf', path: './path/to/file.pdf' }
I'm not sure what's in your content/index or what path this is on, but you obviously need to find a way to make your PDF file ('./path/to/file.pdf') available (as a download). See Express's built-in static server or res.download() to do that.
Once you have the PDF file available as a download, plug that path into PDF.js's .getDocument('/content/file.pdf') and do the rest to render the PDF onto the canvas or whatever.
Hope that helps.
My app is created with mean and I am a user of docker too. The purpose of my app is to create and download a CSV file. I already created my file, compressed it and placed it in a temp folder (the file will be removed after the download). This part is in the nodejs server side and works without problems.
I already use several things like (res.download) which is supposed to download directly the file in the browser but nothing append. I tried to use blob in the angularjs part but it doesn't work.
The getData function creates and compresses the file (it exists I can reach it directly when I look where the app is saved).
exports.getData = function getData(req, res, next){
var listRequest = req.body.params.listURL;
var stringTags = req.body.params.tagString;
//The name of the compressed CSV file
var nameFile = req.body.params.fileName;
var query = url.parse(req.url, true).query;
//The function which create the file
ApollineData.getData(listRequest, stringTags, nameFile)
.then(function (response){
var filePath = '/opt/mean.js/modules/apolline/client/CSVDownload/'+response;
const file = fs.createReadStream(filePath);
res.download(filePath, response);
})
.catch(function (response){
console.log(response);
});
};
My main problem is to download this file directly in the browser without using any variable because it could be huge (like several GB). I want to download it and then delete it.
There is nothing wrong with res.download
Probably the reason why res.download don't work for you is b/c you are using AJAX to fetch the resource, Do a regular navigation. Or if it requires some post data and another method: create a form and submit.
Ok, so I'm trying to print from a webpage (the typical "print" button, but I don't want the print dialog to appear) so I decided to use my already existing node.js backend to do the task (mainly because printing from browser is nearly impossible without the printing dialog).
I found the node-printer (https://github.com/tojocky/node-printer) module, and it works great, but only with text. I tried to send RAW data, but what it does is printing the raw characters. What I actually need is to print a logo, along with some turn information (this is for a customer care facility).
Also, the printer must be installed locally, so I can't use IPP.
Is there any way to print an image, or a combination of images and text with node.js? can it be done through node-printer or is there another way?
I ended calling an exe to do the work for me. I use a child_process to call printhtml, which does all the printing work for me. My code ended this way:
var exec = require('child_process').exec;
exec('printhtml.exe file=file.html', function(err, data) {
console.log(data.toString());
});
Actually, you can print image using node-printer. This work for me
var Printer = require('node-printer');
var fs = require('fs');
// Get available printers list
var listPrinter = Printer.list();
// Create a new Pinter from available devices
var printer = new Printer('YOUR PRINTER HERE. GET IT FROM listPrinter');
// Print from a buffer, file path or text
var fileBuffer = fs.readFileSync('PATH TO YOUR IMAGE');
var jobFromBuffer = printer.printBuffer(fileBuffer);
// Listen events from job
jobFromBuffer.once('sent', function() {
jobFromBuffer.on('completed', function() {
console.log('Job ' + jobFromBuffer.identifier + 'has been printed');
jobFromBuffer.removeAllListeners();
});
});
I had success with the Node IPP package https://www.npmjs.com/package/ipp.
The example code on the docs, which uses another node module PDFKIT to convert your html/file into a PDF, does not work. See my answer here: Cannot print with node js ipp module for a working example.
I am using an API for a Twitch.tv streaming bot called DeepBot.
Here is the link to it on github https://github.com/DeepBot-API/client-websocket
My goal is to create a text document listing all the information pulled from the bot using the command api|get_users|. The bot's response is always a json object. How can I take the json object from the bot and save it as a text file?
Edit: My code
var WebSocket = require('ws');
var ws = new WebSocket('ws://Ip and Port/');
ws.on('open', function () {
console.log('sending API registration');
ws.send('api|register|SECRET');
});
ws.on('close', function close() {
console.log('disconnected');
});
ws.on('message', function (message) {
console.log('Received: ' + message);
});
ws.on('open', function () {
ws.send('api|get_users|');
});
Well that depends on how your setup is? You posted this under javascript. So I guess you are either:
using a browser, to make the websocket connection, in with case there is no direct way to save a file on the client. But in HTML5 you can store key,value pairs with local storage.
using node js (server side javascript) in witch case the code is as below:
some other setup, that I can't guess. in witch case you might tell a little more about it?
In browser with HTML5 capabilities:
// where msg is an object returned from the API
localStorage.setItem('Some key', JSON.stringify(msg));
In Node JS
var fs = require("fs"); // Has to be installed first with “npm install fs”
// where msg is an object returned from the API
fs.writeFile("some-file.json", JSON.stringify(msg), function (err) {
if (err) throw err;
});
Edit: OK, Thanks for clearing it up.
I believe Blag's solution is the way to go.
Good luck with your project!
If it's for a client side JS save :
Create a file in memory for user to download, not through server
and
Convert JS object to JSON string
Is what you need. ( I don't test it, but it'll look like this : )
var j = {"name":"binchen"};
var s = JSON.stringify(j);
window.location = 'data:text/plain;charset=utf-8,'+encodeURIComponent(s);
I am Creating a chat app between two users now I can do Simple text chat with different users using node.js and socket.io. Now problem arises here as I have to send image in chat application and after searching for whole long day I am not able to get perfect node.js in which I can send image in chat app. So I want to know is it possible to send image using node.js. Here is my simple node.js file for sending simple text message from one user to another.
socket.on('privateMessage', function(data) {
socket.get('name', function (err, name) {
if(!err) {
// get the user from list by its name to get its socket,
// then emit event privateMessage
// again here we want to make you clear
// that every single client connection has its own
// unique SOcket Object, we need to get this Socket object
// to communicate with every other client. The socket variable
// in this scope is the client who wants to send the private
// message but the socket of the receiver is not know.
// Get it from the saved list when connectMe handlers gets called
// by each user.
onLine[data.to].emit('newPrivateMessage',{from:name, msg:data.msg, type:'Private Msg'})
}
});
});
You can use the Base64 version of your image and send it like this:
onLine[data.to].emit('newPrivateMessage',{from:name, img:data.img.toString('base64'), type:'Private Msg'})
.. and then on the client side receive it and create an image
socket.on("newPrivateMessage", function(data) {
if (data.img) {
var img = new Image();
img.src = 'data:image/jpeg;base64,' + data.img;
// Do whatever you want with your image.
}
});
UPDATE
The following is a snippet taken from the link I've commented below. As you can see it takes the image from the input, reads it and sends to the server. After that you can send the same data from the server to another client.
For the full example, please read the article.
JavaScript (client)
...
$('#imageFile').on('change', function(e) {
var file = e.originalEvent.target.files[0],
reader = new FileReader();
reader.onload = function(evt) {
var jsonObject = {
'imageData': evt.target.result
}
// send a custom socket message to server
socket.emit('user image', jsonObject);
};
reader.readAsDataURL(file);
});
...
HTML
...
Image file: <input type="file" id="imageFile" /><br/>
...
UPDATE 2
Here is one example I have found:
Java (client)
File file = new File("path/to/the/image");
try {
FileInputStream imageInFile = new FileInputStream(file);
byte imageData[] = new byte[(int) file.length()];
imageInFile.read(imageData);
// Converting Image byte array into Base64 String
String imageDataString = Base64.encodeBase64URLSafeString(imageData);
} catch (...) {
...
}
The above snippet shows how to read the file and encode the data into a base64 string. So then you can send it just like a string (I assume).
Here is the complete example: How to convert Image to String and String to Image in Java?
Also I have found encodeToString function of Base64.Encoder (java.util package), which you can use.
The easiest way I can think of is to simply Base64 encode the image and send it through the text pipe. You would need to distinguish text and image messages with header information (Maybe send a JSON object?).