I have a React Native app that uses the dom-parser module to extract relevant pieces of information from a website, which is not owned by me. The information that I need is loaded dynamically in the page after it finishes loading in the browser. Is there a way to get this in a react native app using fetch()? I don't want the users to see the website open up in the app.
What I've tried:
const html = (await (await fetch(this.search_url)).text()); //get the document
var dom = parser.parseFromString(html); //parse it
var json = dom.getElementsByTagName("script")[5].innerHTML //this is the element that I need
console.log(json)
fetch(this.search_url).then((response)=>response.json()).then((json)=>{
var dom = parser.parseFromString(html);
var json = dom.getElementsByTagName("script")[5].innerHTML
console.log(json)
})
Both of these return a blank response as output. However, when I looked up the source of this.search_url in a browser, it is loading the data after a few seconds of loading the page. Is there a way to get this data in the app? Maybe some trick to make fetch() wait for a few seconds before writing the response?
Related
I made a route on my react app which gets triggered by cron. It is rendering different tiles and after all the tiles are rendered, I'm calling a function. The function is supposed to send a POST req with binary pdf data as formData. How can I achieve that from react-to-pdf?
useEffect(()=>{
let validTiles: any = []
Tiles.forEach((tile: any)=>{
if(checkTile(tile)){
validTiles.push(tile)
}
})
let callFunction: any = validTiles.every((el: any) => values.includes(el));
if(callFunction){
// need to call a POST req with binary data of pdf file from react-to-print
}
},[values])
I am opening a webpage in the cefsharp browser and trying to send a set of JSON data to my website's .aspx page along with query string. While the query string is not an issue but sending the JSON data to the same URL is what I am trying to fix. Earlier I was using Window's native WebBrowser control's Navigate method where I was passing the URL along with query string as well as a byte array. But, I don't find any such method to post the data. Various discussion and posts regarding the same don't have a clear example. Can you provide a sample code/example to show how to achieve that? Here is the code I've been using:
ChromiumWebBrowser browser = new ChromiumWebBrowser();
browser.Address = "https://webhook.site";
browser.Width = System.Windows.SystemParameters.PrimaryScreenWidth;
browser.Height = System.Windows.SystemParameters.PrimaryScreenHeight;
browser.RequestHandler = this;
browser.IsBrowserInitializedChanged += (sender, args) =>
{
if (browser.IsBrowserInitialized)
{
browser.LoadUrlWithPostData("https://webhook.site/#/cba9d04b-01ff-40ef-b223-0917d127ecbe/6ce82e34-28df-4900-88ef-c932a446c6b0/1", Encoding.UTF8.GetBytes("test=123&data=456"));
}
};
I've built a React frontend along with a Rails API only backend. I want to allow the user to create a task and enter a title, description and upload an image.
So I've attempted to use DropZone to get access to the image and then send the image info along with the title and description to my Rails API via a post request using Axios.
I set up Carrierwave on my Rails API in hopes of uploading to an AWS S3 bucket once my Task has been added to the database per the post request.
None of this is working so my question is, should I take care of the image uploading to AWS on the react side and if so, how do I associate that image with the additional information I'm saving to my Rails database (title and description).
Thanks!
First, on React side, there should be no proble with title and description, but for image, you need to encode the image to Base64 string. It is something like this.
getBase64 = (callback) => {
const fileReader = new FileReader();
fileReader.onload = () => {
console.log(fileReader.result);
};
fileReader.readAsDataURL(fileToLoad);
fileReader.onerror = (error) => {
console.log('Error :', error);
};
}
Then, on Axios, send those 3 parameters alltogether with one POST request.
For Rails, you need to set up code that can read the Base64 string. Usually, you can use Paperclip or CarrierWavegem to add image attachment. It will look like this.
property_image = listing.property_images.new(param_image)
if param_image[:file_data]
image_file = Paperclip.io_adapters.for(param_image[:file_data])
image_file.original_filename = param_image[:image_file_name]
image_file.content_type = "image/png"
property_image.image = image_file
end
private
def param_image
params.permit(:image, :image_file_name, :file_data)
end
I am new to SEO and just want to get the idea about how it works for Single Page Application with dynamic content.
In my case, I have a single page application (powered by AngularJS, using router to show different state) that provides some location-based search functionalities, similar to Zillow, Redfin, or Yelp. On mt site, user can type in a location name, and the site will return some results based on the location.
I am trying to figure out a way to make it work well with Google. For example, if I type in "Apartment San Francisco" in Google, the results will be:
And when user click on these links, the sites will display the correct result. I am thinking about having similar SEO like these for my site.
The question is, the page content is purely depending on user's query. User can search by city name, state name, zip code, etc, to show different results, and it's not possible to put them all into sitemap. How google can crawl the content for these kind of dynamic page results?
I don't have experience with SEO and not sure how to do it for my site. Please share some experience or pointers to help me get started. Thanks a lot!
===========
Follow up question:
I saw Googlebot can now run Javascript. I want to understand a bit more of this. When a specific url of my SPA app is opened, it will do some network query (XHR request) for a few seconds and then the page content will be displayed. In this case, will GoogleBot wait for the http response?
I saw some tutorial says we need to prepare static html specifically for Search Engines. If I only want to deal with Google, does it mean I don't have to serve static html anymore because Google can run Javascript?
Thanks again.
If a search engine should come across your JavaScript application then we have the permission to redirect the search engine to another URL that serves the fully rendered version of the page.
For this job
You can either use this tool by Thomas Davis available on github
SEOSERVER
Or
you can use the code below which does the same job as above this code is also available here
Implementation using Phantom.js
We can setup a node.js server that given a URL, it will fully render the page content. Then we will redirect bots to this server to retrieve the correct content.
We will need to install node.js and phantom.js onto a box. Then start up this server below. There are two files, one which is the web server and the other is a phantomjs script that renders the page.
// web.js
// Express is our web server that can handle request
var express = require('express');
var app = express();
var getContent = function(url, callback) {
var content = '';
// Here we spawn a phantom.js process, the first element of the
// array is our phantomjs script and the second element is our url
var phantom = require('child_process').spawn('phantomjs',['phantom-server.js', url]);
phantom.stdout.setEncoding('utf8');
// Our phantom.js script is simply logging the output and
// we access it here through stdout
phantom.stdout.on('data', function(data) {
content += data.toString();
});
phantom.on('exit', function(code) {
if (code !== 0) {
console.log('We have an error');
} else {
// once our phantom.js script exits, let's call out call back
// which outputs the contents to the page
callback(content);
}
});
};
var respond = function (req, res) {
// Because we use [P] in htaccess we have access to this header
url = 'http://' + req.headers['x-forwarded-host'] + req.params[0];
getContent(url, function (content) {
res.send(content);
});
}
app.get(/(.*)/, respond);
app.listen(3000);
The script below is phantom-server.js and will be in charge of fully rendering the content. We don't return the content until the page is fully rendered. We hook into the resources listener to do this.
var page = require('webpage').create();
var system = require('system');
var lastReceived = new Date().getTime();
var requestCount = 0;
var responseCount = 0;
var requestIds = [];
var startTime = new Date().getTime();
page.onResourceReceived = function (response) {
if(requestIds.indexOf(response.id) !== -1) {
lastReceived = new Date().getTime();
responseCount++;
requestIds[requestIds.indexOf(response.id)] = null;
}
};
page.onResourceRequested = function (request) {
if(requestIds.indexOf(request.id) === -1) {
requestIds.push(request.id);
requestCount++;
}
};
// Open the page
page.open(system.args[1], function () {});
var checkComplete = function () {
// We don't allow it to take longer than 5 seconds but
// don't return until all requests are finished
if((new Date().getTime() - lastReceived > 300 && requestCount === responseCount) || new Date().getTime() - startTime > 5000) {
clearInterval(checkCompleteInterval);
console.log(page.content);
phantom.exit();
}
}
// Let us check to see if the page is finished rendering
var checkCompleteInterval = setInterval(checkComplete, 1);
Once we have this server up and running we just redirect bots to the server in our client's web server configuration.
Redirecting bots
If you are using apache we can edit out .htaccess such that Google requests are proxied to our middle man phantom.js server.
RewriteEngine on
RewriteCond %{QUERY_STRING} ^_escaped_fragment_=(.*)$
RewriteRule (.*) http://webserver:3000/%1? [P]
We could also include other RewriteCond, such as user agent to redirect other search engines we wish to be indexed on.
Though Google won't use _escaped_fragment_ unless we tell it to by either including a meta tag; <meta name="fragment" content="!">or using #! URLs in our links.
You will most likely have to use both.
This has been tested with Google Webmasters fetch tool. Make sure you include #! on your URLs when using the fetch tool.
I am using Angular js to show loading screen. It works for all the REST services call except REST service to download the file. I understand why it is not working because for download I am not making any service call using $resource; instead of that I am using normal approach to download the file therefore Angular js code doesn't have any control on start/finish the service request. I tried to use $resource to hit this REST service however I am getting the data from this service and in this case loading screen was working fine however not sure how to use this data to display to user to download in angular way. Following are required details. Please help.
Approach 1 using iframe approach:
/*Download file */
scope.downloadFile = function (fileId) {
//Show loading screen. (Somehow it is not working)
scope.loadingProjectFiles=true;
var fileDownloadURL = "/api/files/" + fileId + "/download";
downloadURL(fileDownloadURL);
//Hide loading screen
scope.loadingProjectFiles=false;
};
var $idown; // Keep it outside of the function, so it's initialized once.
var downloadURL = function (url) {
if ($idown) {
$idown.attr('src', url);
} else {
$idown = $('<iframe>', { id: 'idown', src: url }).hide().appendTo('body');
}
};
Approach 2 using $resource (Not sure how to display data on screen to download)
/*Download file */
scope.downloadFile = function (fileId) {
//Show loading screen (Here loading screen works).
scope.loadingProjectFiles=true;
//File download object
var fileDownloadObj = new DownloadFile();
//Make server call to create new File
fileDownloadObj.$get({ fileid: fileid }, function (response) {
//Q? How to use the response data to display on UI as download popup
//Hide loading screen
scope.loadingProjectFiles=false;
});
};
This is the correct pattern with the $resource service:
scope.downloadFile = function (fileId) {
//Show loading screen (Here loading screen works).
scope.loadingProjectFiles=true;
var FileResource = $resource('/api/files/:idParam', {idParam:'#id'});
//Make server call to retrieve a file
var yourFile = FileResource.$get({ id: fileId }, function () {
//Now (inside this callback) the response data is loaded inside the yourFile variable
//I know it's an ugly pattern but that's what $resource is about...
DoSomethingWithYourFile(yourFile);
//Hide loading screen
scope.loadingProjectFiles=false;
});
};
I agree with you that this is a weird pattern and is different of other APIs where the downloaded data is assigned to a parameter in a callback function, hence your confusion.
Pay attention to the names and the cases of the parameters, and look that there're two mappings involved here, one between the caller to the $resource object and the object itself, and another between this object and the url that it contructs for downloading the actual data.
Here are some idea's for the second approach, you could present the user with a link after the download has happened:
With a "data url". Probably not a good idea for large files.
With a URL like "filesystem:mydownload.zip" You'd first have to save the file with the filesystem API. You can find some inspiration on html5rocks