Module development and code questions

Once I updated a page via admin panel, I need to programatically flush all the caches, then get the page source code and write it to a file. I use the following code inside of my module:

Hi

I'm using headless Drupal via rest API.

i want to create a link that when user open it the user was authenticated to continue purchase a product .

can some one help me?

I want to store some nested data/configuration per user in Drupal. Also the user needs to be able to view/edit it.

Following format:

Hey there. I have some functionality I am working on that relies on Ajax. I have an entity autocomplete that runs the autocompleteclose callback when you select an item from the dropdown list. 

When you do this, if a specific entity type is selected from the list, it adds an additional field to the form. I also have repeatable fields (add/remove another) that runs additional ajax. 

When just doing one item, this works, but once you rebuild the form, the additional field doesn't show up, even if the autocomplete box has the required item. 

Hello All,

I'm a beginner learning Drupal Commerce. Currently, I'm working on a project on E-Learning concepts. My website will have different study materials; some free and some payable. I'm stuck at below major points.

Here I want to test below conditions and display the product details on product page:

1) If the course is free then entire content of the course will be displayed. If payable, then only summary of the course needs to be displayed. If user has purchased this course, then the entire content needs to be displayed

I am completely new to Git or Bitbucket. I don't understand the workflows to use. I need help.

I'am struggling with the best workflow for developing front-end / back-end development in phpstorm and how to manage the files in Git of bitbucket.