How to add content on shopify pages with an app - shopify

Completely new to shopify app development, I looked around the documentation but I did not find any hint about creating an app that add external content to pages (homepage or product pages or every pages) as countdown apps do on every pages or on product pages.
Any help on it could be a great service !

It is really simple these days:
create an App, install it in shop
in app configuration, add an App Proxy
add a JS callback to the App Proxy using a Script Tag (or however you like)
have your App return either a full Liquid string response, or JSON
render response to JS callback in theme
So you can play with this more ways than you can shake a stick. You can return Liquid with your tags so that the web theme designer people can take advantage of what is special about your App. You can just return JSON and template the results into DOM as per the usual pattern.

Related

How to make a shopify app/theme extension which would get displayed in the brand's store UI?

We have an application which integrates with Shopify Clothing stores. We run our application in an iframe inside the shopify store where it interacts with the store's user.
Right now this application gets integrated with Shopify manually by inserting our script tag inside the store's product page. Can someone tell me how I can do this using a shopify app or theme extension?
Edit after David's answer
Is it also possible for me to get information about standard buttons in the theme like the Add to Cart button or Change Variants input. Ideally I would like to get the selector for these.
You would create a Shopify App that asks for permission to write ScriptTags. The Apps simply installs a script tag pointing to your App. So when the merchant installs your App, they get the script tag. Depending on what your App does in that iframe, you may need your Shopify App to provide other support, but that is not detailed in your OP, so I leave it at that.

How to change in template through the Shopify application

I am trying to write a Shopify application and I want to add a section to the product page when the store owner installed my app. I tried this by adding a custom script tag in the shop template and this tag will load and inject my desired HTML into the page. It's work but it needs to force the store owner to change the product page template and its not user-friendly.
I see some apps in the Shopify app store that can change the product page after you install them without needs add any part to the product page template. How they do this work? I can't find the correct way in the Shopify documents.
You can change the Shopify theme of the shop using The API for Assets:
However as drip mentioned this is not a good idea:
If you change the theme auto-magically via code, you are looking for trouble. A lot of things can go wrong - simply you cannot cater for all themes and their changes over time! So you could possibly leave a broken page after the change. The e-shop owner won't be impressed! Actually a lot of the 1* reviews of apps are for that reason!
What would happen if the eshop owner removes your app? He won't know what code to remove.
So, most apps ask the user to add the app code. They provide detailed instructions of course.
Fyi, another problematic approach is the following:
Some apps may attempt to change the DOM "on the fly", by first locating an existing DOM element (a lot of theme-specific if statements to do that with any degree of success) and, then insert the app's DOM elements.
That's very messy and problematic as well, but at least you do not risk ruining the owner's theme files. In the worst case he can uninstall your app and he 'll be ok.

How can I add Javascript into shopify theme with App

I see multiple scopes on Shopify API likes write_themes or write_script_tags to add content in differents files of the theme.
I would like to create an app to add a marketing pixel in differents pages like checkout, index or add_to_cart.
I will need to add a script like :
<script>
...PixelCode...
init('API_KEY', VIEW)
</script>
I will need to set the API_KEY variable dynamique and editable from the panel of the app.
What is the best scope and way to do that ?
Thank you in advance.
Have your App installed in the merchant shop. They approve your App to add script tags. Next up, have your App install the needed script tags. Finally, profit from your hard work.
As for the scopes, writing a script tag only requires that scope. You are not modifying the merchant's theme, so you do not need that scope.

Additional pages with SPA

I'm creating a SPA app using Durandal and I would like to include a credit card payment facility. The guys that I'm looking at requires you to give return URLs to success, cancel and a view other pages, is that possible?
To me it would be breaking the 'single page' part of SPA, but is it possible? Could I do it all in a window?
Disclaimer: I don't know Durandal, but you would solve this in an SPA using either "hashbang URIs" or actually re-serving the SPA in your webserver for the requested return URI and adjusting the content using the same technique as hangbash URIs but using history.pushstate/history.popstate instead, see here: https://developer.mozilla.org/en-US/docs/Web/Guide/API/DOM/Manipulating_the_browser_history
A more general article from Google is available here that covers the same principle: https://developers.google.com/webmasters/ajax-crawling/
This "works" because SPAs are SPAs only in that the browser requests a new HTML document from the server once (or in your case, twice), the SPA should still be updating the history and address-bar state of the UA as the user navigates the application, just as though it were a regular multi-page application.
A great example of this is GitHub's source navigator: Try here ( https://github.com/angular/angular.js ) and navigate the repository, observe that the contents of the file-listing change as does the address bar, but your browser doesn't reload the whole page... yet if you copy+paste the (modified) address bar address into a new browser window, you get the same page back.
I looked into doing credit card processing from a SPA and the best option I had found was Stripe. They supply a javascript file that looks like it would work, I never implemented it on my project due to time constraints so I can't confirm that it works but it looked very promising.
IFRAMEs are quite good for this sort of thing. You can use jQuery to hook an event handler to the page load event and this will tell you when the other end has responded. Load the 3rd party page into the IFRAME and serve response pages on the URLs you provide to the service provider. As mentioned by others you can use routes to identify the response pages. The IFRAME will stop the round-tripping from mucking up your application state and in fact it is possible to put script in your response pages that dot-notates its merry way up the DOM and into your app.

Shopify api: add a link

I am developing a shopify app.
Is it possible to add a new link to the main menu via the shopify API?
Thanks
If you log in to your partner account and then create an App you can edit the created App and you will see all the resources at your disposal where you can add a new link.
If you notice also, using the API you can pull and rewrite any asset in a shop to contain a new link. This is discouraged as bad practice. Instead, inject a script tag that does the dirty work.
Soon as I know the API itself cannot change something inside the theme files... some APPs ask you to apply some code manually in the theme, with proper instructions... maybe this code could add the new menu or dynamically interact to get it.