Hook_file_download Drupal 8 Example

[Bernice Billy]

Call modules that implement hook_file_download() to find out if a file isaccessible and what headers it should be transferred with. If one or moremodules returned headers the download will start with the returned headers.If a module returns -1 drupal_access_denied() will be returned. If the fileexists but no modules responded drupal_access_denied() will be returned.If the file does not exist drupal_not_found() will be returned.

hook_file_download looks like a somewhat likely candidate for triggering an http request to google analytics, but since the hook is responsible for access, it seems possible that another module might deny access after this version of the hook is run, and google analytics would get an event even in cases where the download didn't go through. If there a better hook that would be run after all the access check have finished? I should probably mention that I am using the media module.

hook_file_download drupal 8 example

Download https://t.co/5T3oE1PQWP

Supplementarily, the existence of both hook_file_download and hook_file_download_access is confusing since they both claim to control access to files. Is it a correct understanding that hook_file_download_access basically controls whether a user has access in relation to the entity the file is attached to (so likely would control whether the download link is displayed at all or not), and hook_file_download only applies to private files, and checks on access after a request for the file has been made?

I ended up implementing two hooks: hook_file_download and hood_file_transfer which as far as I could tell is undocumented in the drupal api site as a hook. Both of those hooks calls a function passing the $uri parameter which in turn builds the google analytics request and then sends an http request. That seems to cover the two different cases when a file download passes through drupal for my setup.

So on the assumption that no one else is calling that hook (which you should check for the modules you have installed), a hook_file_download implementation is a perfectly fine place to do something like call a Google API. The only caveat is that if you're calling a web service, you want to make sure it doesn't take so long as to screw up the download.

I'm fairly certain that the hook will be called for any file scheme (i.e., "private:", or a custom scheme). You may want to look at the Drupal 7 Example module "File" example, which I believe shows a hook_file_download implementation.

I think you need to return headers, per the example linked above. It looks like if any module returns a -1 the file access is denied, file not found happens if no headers are returned, otherwise the file is served with the headers the modules returned.

Using the 'private' stream wrapper means that internal links match to /sites/default/files/private (or whatever you have variable_get('file_private_path', '') set to) and external links generate like www.example.com/system/files/...

I'm building a page with different download buttons linked to private zip files. Users have to log in to download. I am using module Permissions by Term to manage who can see which button.

I added a field to user entity to log each download. In hook_file_download() I check, if and how often this file is already downloaded by this user. Up to here everything works fine.

I want to stop or block the download and show a message to the user, if download counter reaches 5 or 10. Is hook_file_download the right hook to achieve this?

As you mention in your question there is a hook_file_download that should work in your case (assuming the file is private). This is not going to work if the file, someone is linking to, is somewhere public such as sites/default/files/abc123.txt.

If you happened to be uploading these private files in a field, then hook_file_download_access would seem more appropriate. This will give you the field that the file belongs to and also the related entity that this field is being used on so you should be able to do more complicated logic such as calling the the appropriate access function to check if the user has access to the field instead of having a hard-coded list in the code.

Now, Drupal is configured to treat all files as private: if visitors want to download a file, or want to look at an image for example, it will be via a Drupal system call and not by directly invoking the file by the browser. In that call Drupal decides whether the visitor concerned has permission to download the file.

After trying out many different setups and modules that added more permission levels and controls, I finally came across a simple hook based fix, for making sure that any file that comes from the private file directory gets it's access checked before downloading. That hook is hook_file_download. I prefer simple code fixes and setups, rather than adding more modules and config to try and manage.

Altough forcing to register seemed a bit strange at first, it's the perfect way to keep the attention to your site.. and for good reasons. Your PDF about file handling rocks! And your implementation of drupal on this site is remarkably good as well.... pfew :)

P.S. I'm on D5 for this project.

P.P.S. Ooooh! Duh! The files have to exist in the database in order for drupal to know anything about their permissions. Hmm.... that's a drag. I really want to have sub-directories for these files, which means I really don't want to use drupal's file upload system.

The files have to exist in the database in order for drupal to know anything about their permissions. Hmm.... that's a drag. I really want to have sub-directories for these files, which means I really don't want to use drupal's file upload system.

i.e. it puts the private directory "two" steps above where the files directory should go (right?)

But if I want to go "three" steps above - since my drupal installation is within drupal directory which eats away a step - what should I put?

When checking to see how different our code was I found the only real difference was that I didn't know about array_rand and was doing it manualy with count() and mt_rand() so I've just changed my code which led me to notice that your example is slightly wrong.

It's interesting that most stuff I've read about drupal file handling is around explicit upload/download though most file handling I care about is putting images in text content. I assume, and so far it works for me, that putting HTML inline in the content - or using tinyMCE/IMCE - the info about file download is just as relevant to those links as to the use of separate attachment lists appended to nodes.

Drupal 7 has now been out for a while and I wonder if your ebook will be useful here, too, if not, I won't bother checking it out.

It would be great to have file downloads in drupal 7 as described above, but I think that all those additional modules are just not yet up to the version...

Am I right? Am I wrong?

I have a drupal form of type file, I want to use this form to upload a photo under the default/files/backgroudimage and than I get the uploaded file path and use it as a backgroud image for some javascript file. my question is I used both $file->uri and file_create_url($file->uri)

So if you want to extend the list, you must implement it via Google Tag Manager. Here is an example of how to configure the trigger. But to learn how to configure the GA4 event tag, read this tutorial.

Choosing your own front-end technology is one of common reasons to choose a decoupled approach. In a decoupled architecture you can also have multiple front-ends at the same time. Contenta gives you examples on how to build a consumer application in different technologies.

Create a latest_posts.info file in the module directory (sites/all/modules/latest_posts/) for telling drupal about your module. latest_posts.info file contains the meta information of your module and it is required for your module. Missing of this file your module will not appear in the module listing.

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