There are a lot of cool tools for making powerful "single-page" JavaScript websites nowadays. In my opinion, this is done right by letting the server act as an API (and nothing more) and letting the client handle all of the HTML generation stuff. The problem with this "pattern" is the lack of search engine support. I can think of two solutions:
When the user enters the website, let the server render the page exactly as the client would upon navigation. So if I go to http://example.com/my_path directly the server would render the same thing as the client would if I go to /my_path through pushState.
Let the server provide a special website only for the search engine bots. If a normal user visits http://example.com/my_path the server should give him a JavaScript heavy version of the website. But if the Google bot visits, the server should give it some minimal HTML with the content I want Google to index.
The first solution is discussed further here. I have been working on a website doing this and it's not a very nice experience. It's not DRY and in my case I had to use two different template engines for the client and the server.
I think I have seen the second solution for some good ol' Flash websites. I like this approach much more than the first one and with the right tool on the server it could be done quite painlessly.
So what I'm really wondering is the following:
Can you think of any better solution?
What are the disadvantages with the second solution? If Google in some way finds out that I'm not serving the exact same content for the Google bot as a regular user, would I then be punished in the search results?
While #2 might be "easier" for you as a developer, it only provides search engine crawling. And yes, if Google finds out your serving different content, you might be penalized (I'm not an expert on that, but I have heard of it happening).
Both SEO and accessibility (not just for disabled person, but accessibility via mobile devices, touch screen devices, and other non-standard computing / internet enabled platforms) both have a similar underlying philosophy: semantically rich markup that is "accessible" (i.e. can be accessed, viewed, read, processed, or otherwise used) to all these different browsers. A screen reader, a search engine crawler or a user with JavaScript enabled, should all be able to use/index/understand your site's core functionality without issue.
pushState does not add to this burden, in my experience. It only brings what used to be an afterthought and "if we have time" to the forefront of web development.
What your describe in option #1 is usually the best way to go - but, like other accessibility and SEO issues, doing this with pushState in a JavaScript-heavy app requires up-front planning or it will become a significant burden. It should be baked in to the page and application architecture from the start - retrofitting is painful and will cause more duplication than is necessary.
I've been working with pushState and SEO recently for a couple of different application, and I found what I think is a good approach. It basically follows your item #1, but accounts for not duplicating html / templates.
Most of the info can be found in these two blog posts:
http://lostechies.com/derickbailey/2011/09/06/test-driving-backbone-views-with-jquery-templates-the-jasmine-gem-and-jasmine-jquery/
and
http://lostechies.com/derickbailey/2011/06/22/rendering-a-rails-partial-as-a-jquery-template/
The gist of it is that I use ERB or HAML templates (running Ruby on Rails, Sinatra, etc) for my server side render and to create the client side templates that Backbone can use, as well as for my Jasmine JavaScript specs. This cuts out the duplication of markup between the server side and the client side.
From there, you need to take a few additional steps to have your JavaScript work with the HTML that is rendered by the server - true progressive enhancement; taking the semantic markup that got delivered and enhancing it with JavaScript.
For example, i'm building an image gallery application with pushState. If you request /images/1 from the server, it will render the entire image gallery on the server and send all of the HTML, CSS and JavaScript down to your browser. If you have JavaScript disabled, it will work perfectly fine. Every action you take will request a different URL from the server and the server will render all of the markup for your browser. If you have JavaScript enabled, though, the JavaScript will pick up the already rendered HTML along with a few variables generated by the server and take over from there.
Here's an example:
<form id="foo">
Name: <input id="name"><button id="say">Say My Name!</button>
</form>
After the server renders this, the JavaScript would pick it up (using a Backbone.js view in this example)
FooView = Backbone.View.extend({
events: {
"change #name": "setName",
"click #say": "sayName"
},
setName: function(e){
var name = $(e.currentTarget).val();
this.model.set({name: name});
},
sayName: function(e){
e.preventDefault();
var name = this.model.get("name");
alert("Hello " + name);
},
render: function(){
// do some rendering here, for when this is just running JavaScript
}
});
$(function(){
var model = new MyModel();
var view = new FooView({
model: model,
el: $("#foo")
});
});
This is a very simple example, but I think it gets the point across.
When I instante the view after the page loads, I'm providing the existing content of the form that was rendered by the server, to the view instance as the el for the view. I am not calling render or having the view generate an el for me, when the first view is loaded. I have a render method available for after the view is up and running and the page is all JavaScript. This lets me re-render the view later if I need to.
Clicking the "Say My Name" button with JavaScript enabled will cause an alert box. Without JavaScript, it would post back to the server and the server could render the name to an html element somewhere.
Edit
Consider a more complex example, where you have a list that needs to be attached (from the comments below this)
Say you have a list of users in a <ul> tag. This list was rendered by the server when the browser made a request, and the result looks something like:
<ul id="user-list">
<li data-id="1">Bob
<li data-id="2">Mary
<li data-id="3">Frank
<li data-id="4">Jane
</ul>
Now you need to loop through this list and attach a Backbone view and model to each of the <li> items. With the use of the data-id attribute, you can find the model that each tag comes from easily. You'll then need a collection view and item view that is smart enough to attach itself to this html.
UserListView = Backbone.View.extend({
attach: function(){
this.el = $("#user-list");
this.$("li").each(function(index){
var userEl = $(this);
var id = userEl.attr("data-id");
var user = this.collection.get(id);
new UserView({
model: user,
el: userEl
});
});
}
});
UserView = Backbone.View.extend({
initialize: function(){
this.model.bind("change:name", this.updateName, this);
},
updateName: function(model, val){
this.el.text(val);
}
});
var userData = {...};
var userList = new UserCollection(userData);
var userListView = new UserListView({collection: userList});
userListView.attach();
In this example, the UserListView will loop through all of the <li> tags and attach a view object with the correct model for each one. it sets up an event handler for the model's name change event and updates the displayed text of the element when a change occurs.
This kind of process, to take the html that the server rendered and have my JavaScript take over and run it, is a great way to get things rolling for SEO, Accessibility, and pushState support.
Hope that helps.
I think you need this: http://code.google.com/web/ajaxcrawling/
You can also install a special backend that "renders" your page by running javascript on the server, and then serves that to google.
Combine both things and you have a solution without programming things twice. (As long as your app is fully controllable via anchor fragments.)
So, it seem that the main concern is being DRY
If you're using pushState have your server send the same exact code for all urls (that don't contain a file extension to serve images, etc.) "/mydir/myfile", "/myotherdir/myotherfile" or root "/" -- all requests receive the same exact code. You need to have some kind url rewrite engine. You can also serve a tiny bit of html and the rest can come from your CDN (using require.js to manage dependencies -- see https://stackoverflow.com/a/13813102/1595913).
(test the link's validity by converting the link to your url scheme and testing against existence of content by querying a static or a dynamic source. if it's not valid send a 404 response.)
When the request is not from a google bot, you just process normally.
If the request is from a google bot, you use phantom.js -- headless webkit browser ("A headless browser is simply a full-featured web browser with no visual interface.") to render html and javascript on the server and send the google bot the resulting html. As the bot parses the html it can hit your other "pushState" links /somepage on the server mylink, the server rewrites url to your application file, loads it in phantom.js and the resulting html is sent to the bot, and so on...
For your html I'm assuming you're using normal links with some kind of hijacking (e.g. using with backbone.js https://stackoverflow.com/a/9331734/1595913)
To avoid confusion with any links separate your api code that serves json into a separate subdomain, e.g. api.mysite.com
To improve performance you can pre-process your site pages for search engines ahead of time during off hours by creating static versions of the pages using the same mechanism with phantom.js and consequently serve the static pages to google bots. Preprocessing can be done with some simple app that can parse <a> tags. In this case handling 404 is easier since you can simply check for the existence of the static file with a name that contains url path.
If you use #! hash bang syntax for your site links a similar scenario applies, except that the rewrite url server engine would look out for _escaped_fragment_ in the url and would format the url to your url scheme.
There are a couple of integrations of node.js with phantom.js on github and you can use node.js as the web server to produce html output.
Here are a couple of examples using phantom.js for seo:
http://backbonetutorials.com/seo-for-single-page-apps/
http://thedigitalself.com/blog/seo-and-javascript-with-phantomjs-server-side-rendering
If you're using Rails, try poirot. It's a gem that makes it dead simple to reuse mustache or handlebars templates client and server side.
Create a file in your views like _some_thingy.html.mustache.
Render server side:
<%= render :partial => 'some_thingy', object: my_model %>
Put the template your head for client side use:
<%= template_include_tag 'some_thingy' %>
Rendre client side:
html = poirot.someThingy(my_model)
To take a slightly different angle, your second solution would be the correct one in terms of accessibility...you would be providing alternative content to users who cannot use javascript (those with screen readers, etc.).
This would automatically add the benefits of SEO and, in my opinion, would not be seen as a 'naughty' technique by Google.
Interesting. I have been searching around for viable solutions but it seems to be quite problematic.
I was actually leaning more towards your 2nd approach:
Let the server provide a special website only for the search engine
bots. If a normal user visits http://example.com/my_path the server
should give him a JavaScript heavy version of the website. But if the
Google bot visits, the server should give it some minimal HTML with
the content I want Google to index.
Here's my take on solving the problem. Although it is not confirmed to work, it might provide some insight or idea's for other developers.
Assume you're using a JS framework that supports "push state" functionality, and your backend framework is Ruby on Rails. You have a simple blog site and you would like search engines to index all your article index and show pages.
Let's say you have your routes set up like this:
resources :articles
match "*path", "main#index"
Ensure that every server-side controller renders the same template that your client-side framework requires to run (html/css/javascript/etc). If none of the controllers are matched in the request (in this example we only have a RESTful set of actions for the ArticlesController), then just match anything else and just render the template and let the client-side framework handle the routing. The only difference between hitting a controller and hitting the wildcard matcher would be the ability to render content based on the URL that was requested to JavaScript-disabled devices.
From what I understand it is a bad idea to render content that isn't visible to browsers. So when Google indexes it, people go through Google to visit a given page and there isn't any content, then you're probably going to be penalised. What comes to mind is that you render content in a div node that you display: none in CSS.
However, I'm pretty sure it doesn't matter if you simply do this:
<div id="no-js">
<h1><%= #article.title %></h1>
<p><%= #article.description %></p>
<p><%= #article.content %></p>
</div>
And then using JavaScript, which doesn't get run when a JavaScript-disabled device opens the page:
$("#no-js").remove() # jQuery
This way, for Google, and for anyone with JavaScript-disabled devices, they would see the raw/static content. So the content is physically there and is visible to anyone with JavaScript-disabled devices.
But, when a user visits the same page and actually has JavaScript enabled, the #no-js node will be removed so it doesn't clutter up your application. Then your client-side framework will handle the request through it's router and display what a user should see when JavaScript is enabled.
I think this might be a valid and fairly easy technique to use. Although that might depend on the complexity of your website/application.
Though, please correct me if it isn't. Just thought I'd share my thoughts.
Use NodeJS on the serverside, browserify your clientside code and route each http-request's(except for static http resources) uri through a serverside client to provide the first 'bootsnap'(a snapshot of the page it's state). Use something like jsdom to handle jquery dom-ops on the server. After the bootsnap returned, setup the websocket connection. Probably best to differentiate between a websocket client and a serverside client by making some kind of a wrapper connection on the clientside(serverside client can directly communicate with the server). I've been working on something like this: https://github.com/jvanveen/rnet/
Use Google Closure Template to render pages. It compiles to javascript or java, so it is easy to render the page either on the client or server side. On the first encounter with every client, render the html and add javascript as link in header. Crawler will read the html only but the browser will execute your script. All subsequent requests from the browser could be done in against the api to minimize the traffic.
This might help you : https://github.com/sharjeel619/SPA-SEO
Logic
A browser requests your single page application from the server,
which is going to be loaded from a single index.html file.
You program some intermediary server code which intercepts the client
request and differentiates whether the request came from a browser or
some social crawler bot.
If the request came from some crawler bot, make an API call to
your back-end server, gather the data you need, fill in that data to
html meta tags and return those tags in string format back to the
client.
If the request didn't come from some crawler bot, then simply
return the index.html file from the build or dist folder of your single page
application.
I am new scraping with Python and BeautifulSoup4. Also, I do not have knowledge of HTML. To practice, I am trying to use it on Carrefour website to extract the price and price per kilogram of the product that I search for EAN code.
My code:
barcodes = ['5449000000996']
for barcode in barcodes:
url = 'https://www.carrefour.es/?q=' + barcode
html = requests.get(url).content
bs = BeautifulSoup(html, 'lxml')
searchingprice = bs.find_all('strong', {'class':'ebx-result-price__value'})
print(searchingprice)
searchingpricerperkg = bs.find_all('span', {'class':'ebx-result__quantity ebx-result-quantity'})
print(searchingpricerperkg)
But I do not get any result at all
Here is a screenshot of the HTML code:
What am I doing wrong? I tried with other website and it seems to work
The problem here is that you're scraping a page with Javascript-generated content. Basically, the page that you're grabbing with requests actually doesn't have the thing you're grabbing from it - it has a bunch of javascript. When your browser goes to the page, it runs the javascript, which generates the content - so the page you see in the rendered version in your browser is not the same thing returned from the actual page itself. The page contains instructions for your browser to write the page that you see.
If you're just practicing, you might want to simply try a different source to scrape from, but to scrape from this page, you'll need to look into other solutions that can handle javascript generated content:
Web-scraping JavaScript page with Python
Alternatively, the javascript generates content by requesting data from other sources. I don't speak spanish, so I'm not much help in figuring this part out, but you might be able to.
As an exercise, go ahead and have BS4 prettify and print out the page that it receives. You'll see that within that page there are requests to other locations to get the info you're asking for. You might be able to change your request to not go to the page where you view the info, but to the location that page gets it's data from.
Im trying to scrape a div class but everything I have tried has failed so far :(
Im trying to scrape the element(s):
<a href="http://www.bellator.com/events/d306b5/bellator-newcastle-pitbull-vs-
scope"><div class="s_buttons_button s_buttons_buttonAlt
s_buttons_buttonSlashBack">More info</div></a>
from the website: http://www.bellator.com/events
I tried accessing the list of elements by doing
Elements elements = document.select("div[class=s_container] > li");
but that didnt return anything.
Then i tried accessing just the parent with
Elements elements = document.select("div[class=s_container]");
and that returned two div with classname "s_container", non of which is the one I needed :<
then i tried accessing that ones parent with
Elements elements = document.select("div[class=ent_m152_bellator module
ent_m152_bellator_V1_1_0 ent_m152]");
And that didnt return anything
I also tried
Elements elements = document.select("div[class=ent_m152_bellator]");
because I wasnt sure about the white spaces but it didnt return anything either
Then I tried accessing its parent by
Elements elements = document.select("div#t3_lc");
and that worked, but it returned an element containing
<div id="t3_lc">
<div class="triforce-module" id="t3_lc_promo1"></div>
</div>
which is kinda weird because i cant see that it has that child when i inspect the website in chrome :S
Anyone knows whats going on? I feel kinda lost..
What you see in your web browser is not what Jsoup sees. Disable JavaScript and refresh page to get what Jsoup gets OR press CTRL+U ("Show source", not "Inspect"!) in your browser to see original HTML document before JavaScript modifications. When you use your browser's debugger it shows final document after modifications so it's not not suitable for your needs.
It seems like whole "UPCOMING EVENTS" section is dynamically loaded by JavaScript.
Even more, this section is asynchronously loaded with AJAX. You can use your browsers debugger (Network tab) to see every possible request and response.
I found it but unfortunately all the data you need is returned as JSON so you're going to need another library to parse JSON.
That's not the end of the bad news and this case is more complicated. You could make direct request for the data:
http://www.bellator.com/feeds/ent_m152_bellator/V1_1_0/d10a728c-547e-4a6f-b140-7eecb67cff6b
but the URL seems random and few of these URLs (one per upcoming event?) are included inside JavaScript code in HTML.
My approach would be to get the URLs of these feeds with something like:
List<String> feedUrls = new ArrayList<>();
//select all the scripts
Elements scripts = document.select("script");
for(Element script: scripts){
if(script.text().contains("http://www.bellator.com/feeds/")){
// here use regexp to get all URLs from script.text() and add them to feedUrls
}
}
for(String feedUrl : feedUrls){
// iterate over feed URLs, download each of them
String json = Jsoup.connect(feedUrl).ignoreContentType(true).get().body().toString();
// here use JSON parsing library to get the data you need
}
ALTERNATIVE approach would be to stop using Jsoup because of its limitations and use Selenium Webdriver as it supports dynamic page modifications by JavaScript so you'd get the HTML of the final result - exactly what you see in web browser and Inspector.
If anyone finds this in the future; I managed to solve it with Selenium, dont know if its a good/correct solution but it seems to be working.
System.setProperty("webdriver.chrome.driver", "C:\\Users\\PC\\Desktop\\Chromedriver\\chromedriver.exe");
WebDriver driver = new ChromeDriver();
driver.get("http://www.bellator.com/events");
String html = driver.getPageSource();
Document doc = Jsoup.parse(html);
Elements elements = doc.select("ul.s_layouts_lineListAlt > li > a");
for(Element element : elements) {
System.out.println(element.attr("href"));
}
Output:
http://www.bellator.com/events/d306b5/bellator-newcastle-pitbull-vs-scope
http://www.bellator.com/events/ylcu8d/bellator-215-mitrione-vs-kharitonov
http://www.bellator.com/events/yk2djw/bellator-216-mvp-vs-daley
http://www.bellator.com/events/e8rdqs/bellator-217-gallagher-vs-graham
http://www.bellator.com/events/281wxq/bellator-218-sanchez-vs-grimshaw
http://www.bellator.com/events/8lcbdi/bellator-219-koreshkov-vs-larkin
http://www.bellator.com/events/9rqguc/bellator-macdonald-vs-fitch
I am new in Angular
What I am going to try is to get the HTML of a page and reproduce it into an iFrame (it is an exercise).
I am using the following piece of code:
var prova = this._http.get(myUrl, {responseType: "text"}).subscribe((x) =>{
console.log(x);
});
I did it on a website (if is needed I can also insert the name of the pages) and it returns the html only of some pages.
In the other case the string x is empty.
Could it depend on connection?
Or there is some way to wait the end of the get request?
Or simply is wrong my approach and I should make a different type of request?
Your most likely going to need to use a library like puppeteer if you want to render a page properly. Puppeteer is a node library and useless headless chrome so I am not sure how well you could really integrate with Angular.
https://github.com/GoogleChrome/puppeteer
I need to scrape some URLs from some retailer product pages, but the specific URLs I need to get aren't in the html part of the page. The html looks like this for each of the items on which one would click to get to the page with the URL I need to grab:
<div id="name" class="hand bold" onclick="AVON.productcontrol.Go(45714);">ADVANCE TECHNIQUES Color Protection Conditioner Bonus Size</div>
I wrote the following to get URLs from the page, but since the actual URLs I need don’t seem to be stored in the page, it doesn’t get what I need:
def getUrls(URL):
"""input: product page url
output: list of urls to products
"""
connection = urllib.urlopen(URL)
dom = lxml.html.fromstring(connection.read())
selAnchor = CSSSelector('a')
foundElements = selAnchor(dom)
urlList = [e.get('href') for e in foundElements]
return urlList
Is there a way to get the link that the function after ‘onclick’ (I guess AVON.productcontrol.Go(#);) takes you to? I don’t fully understand html, and while I’ve read a bit about onclick, I can’t figure out how the function after 'onclick' works.
In order to find the URL that you are taken to on click, you need to find the JavaScript source code of the 'Go' function and read and understand it. It's buried somewhere within a tag or some JavaScript .js file that is referenced directly or indirectly by the HTML page. Happy digging!
Or: you automate the interaction with the web page with a tool like Selenium (http://docs.seleniumhq.org/) and just check where it takes you if you click.