Get path to file in storage - laravel

I saved a file to storage using:
$request->file('avatar')->store('avatars');
Which saved it to:
storage/app/avatars/avatar.png
How can I get the path to this file/folder (not the URL)? What is the correct way to do this using Laravel's Filesystem?

There is no correct way to do this; because it should not be done. The Storage is an opaque system to talk to different storage systems; as such there is no api to get the backing file path. As an example, that wouldn't work with Amazon S3. The only path your application knows about is the string you send to the Storage facade to work with the file, there are no guarantees that this string is used to generate the filename when the storage system stores the file.
There are some hacks you can use that works for the local disk, but those are not available for the Storage system in general. Using these solutions means that you'll limit yourself to only use the local disk; this will cause you troubles when you need to scale out and add another server. You'll then have two servers with two separate local disks, with separate content.
The correct way to work with the files, that will work for all configurations, is to get the file content (Storage::get), do the modifications (including storing them in a temporary file) and then write back the new file content (Storage::set).
If you're really sure that you will only ever use the local filesystem, use the File facade instead of the Storage facade. I'm unable to find any documentation for this, only the interface it exposes.
Reference: https://github.com/laravel/framework/issues/13610

Try this
storage_path('app/avatars/avatar.png');

you can only get the storage folder path from laravel function, you can give nested folder name after it, it will bind the base url as well
storage_path(folder1/folder2/.../file.png);

Related

how to temporary store uploaded files using FLASK

I'm creating a web application using flask that takes 3 input from the user: name, picture, grades.
I want to store these information temporary depending on the user's session.
and as a beginner I read that sessions are not for storing files, what other secure way you recommend me to use?
I would recommend to write the files to disk.
If this is really temporary, e.g. you have a two-step-sign-up-form, you could write the files to temporary files or into a temporary directory.
Please see the excellent documentation at https://docs.python.org/3/library/tempfile.html
Maybe this should not be this temporary? It sounds like a user picture is something more permanent.
Then I would recommend e.g. to create a directory for each user and store the files there.
This is done with standard Python io, e.g with the open function.
More info about reading and writing files also can be found in the official Python documentation:
https://docs.python.org/3/tutorial/inputoutput.html#reading-and-writing-files

Windows Projected File System read only?

I tried to play around with Projected File System to implement a user mode ram drive (previously I had used Dokan). I have two questions:
Is this a read-only projection? I could not find anything any notification sent to me when opening the file from say Notepad and writing to it.
Is the file actually created on the disk once I use PrjWriteFileData()? From what I have understood, yes.
In that case what would be any useful thing that one could do with this library if there is no writing to the projected files? It seems to me that the only useful thing is to initially create a directory tree from somewhere else (say, a remote repo), but nothing beyond that. Dokan still seems the way to go.
The short answer:
It's not read-only but you can't write your files directly to a "source" filesystem via a projected one.
WriteFileData method is used for populating placeholder files on the "scratch" (projected) file system, so, it doesn't affect a "source" file system.
The long answer:
As stated in the comment by #zett42 ProjFS was mainly designed as a remote git file system. So, the main goal of any file versioning system is to handle multiple versions of files. From this a question arise - do we need to override the file inside a remote repository on ProjFS file write? It would be disastrous. When working with git you always write files locally and they are not synced until you push the changes to a remote repository.
When you enumerate files nothing being written to a local file system. From the ProjFS documentation:
When a provider first creates a virtualization root it is empty on the
local system. That is, none of the items in the backing data store
have yet been cached to disk.
Only after the file is opened ProjFS creates a "placeholder" for it in a local file system - I assume that it's a file with a special structure (not a real one).
As files and directories under the virtualization root are opened, the
provider creates placeholders on disk, and as files are read the
placeholders are hydrated with contents.
What "hydrated" is mean? Most likely, it represents a special data structure partially filled with real data. I would imaginge a placeholder as a sponge partially filled with data.
As items are opened, ProjFS requests information from the provider to allow placeholders for those items to be created in the local file system. As item contents are accessed, ProjFS requests those contents from the provider. The result is that from the user's perspective, virtualized files and directories appear similar to normal files and directories that already reside on the local file system.
Only after a file is updated (modified). It's not a placeholder anymore - it becomes "Full file/directory":
For files: The file's content (primary data stream) has been modified.
The file is no longer a cache of its state in the provider's store.
Files that have been created on the local file system (i.e. that do
not exist in the provider's store at all) are also considered to be
full files.
For directories: Directories that have been created on the local file
system (i.e. that do not exist in the provider's store at all) are
considered to be full directories. A directory that was created on
disk as a placeholder never becomes a full directory.
It means that on the first write the placeholder is replaced by the real file in the local FS. But how to keep a "remote" file in sync with a modified one? (1)
When the provider calls PrjWritePlaceholderInfo to write the
placeholder information, it supplies the ContentID in the VersionInfo
member of the placeholderInfo argument. The provider should then
record that a placeholder for that file or directory was created in
this view.
Notice "The provider should then record that a placeholder for that file". It means that in order to sync the file later with a correct view representation we have to remember with which version a modified file is associated. Imagine we are in a git repository and we change the branch. In this case, we may update one file multiple times in different branches. Now, why and when the provider calls PrjWritePlaceholderInfo?
... These placeholders represent the state of the backing store at the
time they were created. These cached items, combined with the items
projected by the provider in enumerations, constitute the client's
"view" of the backing store. From time to time the provider may wish
to update the client's view, whether because of changes in the backing
store, or because of explicit action taken by the user to change their
view.
Once again, imagine switching branches in a git repository; you have to update a file if it's different in another branch. Continuing answering the question (1). Imaging you want to make a "push" from a particular branch. First of all, you have to know which files are modified. If you are not recorded the placeholder info while modifying your file you won't be able to do it correctly (at least for the git repository example).
Remember, that a placeholder is replaced by a real file on modification? A ProjFS has OnNotifyFileHandleClosedFileModifiedOrDeleted event. Here is the signature of the callback:
public void NotifyFileHandleClosedFileModifiedOrDeletedCallback(
string relativePath,
bool isDirectory,
bool isFileModified,
bool isFileDeleted,
uint triggeringProcessId,
string triggeringProcessImageFileName)
For our understanding, the most important parameter for us here is relativePath. It will contain a name of a modified file inside the "scratch" file system (projected). Here you also know that the file is a real file (not a placeholder) and it's written to the disk (that's it you won't be able to intercept the call before the file is written). Now you may copy it to the desired location (or do it later) - it depends on your goals.
Answering the question #2, it seems like PrjWriteFileData is used only for populating "scratch" file system and you cannot use it for updating the "source" file system.
Applications:
As for applications, you still can implement a remote file system (instead of using Dokan) but all writes will be cached locally instead of directly written to a remote location. A couple use case ideas:
Distributed File Systems
Online Drive Client
A File System "Dispatcher" (for example, you may write your files in different folders depending on particular conditions)
A File Versioning System (for example, you may preserve different versions of the same file after a modification)
Mirroring data from your app to a file system (for example, you can "project" a text file with indentations to folders, sub-folders and files)
P.S.: I'm not aware of any undocumented APIs, but from my point of view (accordingly with the documentation) we cannot use ProjFS for purposes like a ramdisk or write files directly to the "source" file system without writing them to the "local" file system first.

How can I use named pipes to stream a GCP Cloud Storage object to an executable that wants input files?

I have a third-party executable that takes a directory path as an argument and in turn looks there for a collection of .db files. I have said collection of files stored in a Google Cloud Storage bucket and would like to stream the content of those files into some local named pipes that can be used as input to the executable.
I'm writing an application to perform the above in Go and am using the "cloud.google.com/go/storage" package to work with cloud storage objects.
As a note, I need all pipes/files to be available for reading at the time I run the executable.
What is the best way to go about this? I'm looking to essentially used the named pipe as a proxy of sorts to make remote files look local to this executable. Possible?

What's the proper storage location for a database for a cross platform command line program?

I wrote a simple note taking program that's nothing more than a dictionary mapping a key to a value. IE
$ hlp -key age -value 25
$ hlp age
25
and it just stores information in a json file hardcoded to ~/.hlp.json. But I was wondering if there's likely some standard location I should be putting this file. Is there a standard location for databases like this?
A useful resource here is the hier(7) man page. (http://linux.die.net/man)
Data that is only going to be used by you belongs in $HOME, traditionally hosted under /home.
For something that is used to support the system itself, you'd be using /var. For applications that are just hosted on the system, you'd use /var/opt.
If the application is something big that could be replicated or moved to another system, you'd create a separate filesystem with a mount point outside any of those listed in hier(7). This could be a filesystem mounted from a SAN or NAS, which whould help mobility of the application.
Once you actually need to access the data from different machines, you'd have to move it to a network accessable key/value store or sql database.

What is a good way to access external data from aws

I would like to access external data from my aws ec2 instance.
In more detail: I would like to specify inside by user-data the name of a folder containing about 2M of binary data. When my aws instance starts up, I would like it to download the files in that folder and copy them to a specific location on the local disk. I only need to access the data once, at startup.
I don't want to store the data in S3 because, as I understand it, this would require storing my aws credentials on the instance itself, or passing them as userdata which is also a security risk. Please correct me if I am wrong here.
I am looking for a solution that is both secure and highly reliable.
which operating system do you run ?
you can use an elastic block storage. it's like a device you can mount at boot (without credentials) and you have permanent storage there.
You can also sync up instances using something like Gluster filesystem. See this thread on it.

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