I have a program in c# that downloads images from a web service.
The download usually takes time so I want to save the images locally so I would only need to download each image once. The problem with that is when the images saves the user of the program can see the image in the files and change it.
Is there a way to save the image in the program, yet keep it from users to see and change in the folder?
EDIT: solution used:
Encrypting the images and their names when I save them, and only access them this way. (decrypting when after reading them).
What is your intent? Anything your program has access to do, your user does as well. If you're just trying to prevent people from accidentally mucking with your images, then save off a SHA1 or similar hash of the file and store it separately. When you need an image, check the SHA1 and redownload if it doesn't match. This will prevent casual tampering, but still isn't 100% effective against malicious changes.
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Currently working in an intern project, where i am required to add an image when adding an employee in my table.
we are using angularJS in front end and asp.net core 3.1 in backend, we have sql database using SSMS, i couldnt get it how to upload images, my senior told me to store the path in db, if i am to store the path in db, where will my images be uploaded, i did upload the images making an api on wwwroot folder, but they marked it as a bad practice? So can any of you guide me? Thankyou in advance :)
Steve's Comment is useful. You can upload image to the new folder under the wwwroot. You can refer the blog fisrt, it create a Resources folder, and it also use angular.
In general, we still do not recommend storing pictures under wwwroot. Regardless of whether you create a subfolder such as Sources.
Reason：
As the business increases, or over time, the contents under the folder will definitely increase. Even if the hard disk space at the deployment site is large, it will cause subsequent maintenance problems.
Specifically, the picture file may be accidentally deleted and cannot be recovered subsequently. If the picture file ends up taking up a lot of space, it will run out of hard disk space.
The Best Practice:
Upload the image to the cloud drive, something like: azure storage. And save the path to your database. It will save your disk space and it will also relieve your server stress, and more safety.
Additional tips:
If you just store a very small avatar file, we can convert it to base64 string format and store it in the database. In the absence of cloud services, some tiny images can be realized in this way.
However, this is not suitable for growing business scenarios, because it will cause the database footprint to become larger, which is not conducive to synchronization or backup. As well as poor large files, it may cause problems with the loading of files.
I have an ASP.NET website that stores large numbers of files such as videos. I want an easy way to allow the user to download all the files in a single package. I was thinking about creating ZIP files dynamically.
All the examples I have seen involve creating the file before it is downloaded but potentially terabytes of information will be downloaded and therefor the user will have a long wait. Apparently ZIP files store all the information regarding what is in the ZIP file at the end of the file.
My idea is to dynamically create the file as its downloaded. This way I could allow the user to click download. The download would start and not require any space on the server to be pre packaged as it would copy things over uncompressed sequentially. The final part of the file would contain the information on the contents of what has been downloaded.
Has anyone had any experience of this? Does anyone know a better way of doing this? At the moment I cant see any pre made utilities for doing this but I believe it will work. If it doesn't exist then i'm thinking that I will have to read the Zip file format specifications and write my own code... something that will take more time than I was intending to spend on this.
https://pkware.cachefly.net/webdocs/casestudies/APPNOTE.TXT
With a backup application, a good and space-efficient way to back up is to detect changes in files. Some online services such as Dropbox do this as well since Dropbox includes version history. How do backup applications detect changes in files and store them?
If you have a monumentally large file which has already been backed up, and you make a small change (such as in a Microsoft Word document), how can an application detect a change and process it? If the file has changes made often, there must be an efficient algorithm to only process changes and not the entire file. Is there an algorithm to do this in C# .NET?
Edit: I'm trying to figure out how to encode two files as the original and the changes (in a VCDIFF format or etc.) I know how to use the format and decode it just fine.
to detect changes, you can compute the Hash code (such as MD5) for the original and the modified versions of the file. if they are identical, no changes are made.
I think DropBox has its own protocol to detect which part of this file is modified.
you can figure out to find out your own way, for example, divide the file to fixed-size parts, store their hash codes. when the client download the file, send these information to the client. after modifying the file, recalculate the hash codes for the parts, compare them with original hash codes, upload the parts that were modified, rebuild the file from original parts and the modified parts.
rsync is an open source tool that synchronizes files using delta encoding.
----------------------------------------------------EDIT: my idea above is very simple and not efficient. you can a look at VCDIFF that were explained by research paper and implemented in many languages (C#).
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Possible Duplicate:
Storing Images in DB - Yea or Nay?
Pretty straight forward, I am hosting a site where users can upload pictures, and I have a .net File upload control working appropriately.. I'm just wondering what methodology I should use to store them on the server..
I can use the SaveAs() method off the FileUpload control which saves it as an actual file..
I can break the image down to a Byte[] and store it in the database for access.
I believe the real question here is.. Do I want the load on IIS or Sql Server 2008 R2?
What's the general consensus on which methodology I should use and why? Thanks!
There is no general consensus, because neither method is ideal.
Storing the images as files means that it becomes harder to scale the application to run on multiple servers. Then you would need a SAN/NAS to store the files instead of a local disk.
Storing the images in the database means that you are using a lot of the cache space for image data, slowing down other queries, and it also increases the size of the database, and the backups. It also means that you have to serve the images through a page, you can't just request the file directly.
So, it comes down to how much images you will have, and how scalable you need the application to be.
Avoid getting them in the database. That will make your DB a lot larger in size just because of a few files. That also affects the backup size.
I do not see any real gain on having the actual file bytes in the database. If you have the physical path to the file in the file system, that would suffice.
That also allows you to have your own backup strategy for the files.
In my C# windows application (using visual C# 2012 if you need to know) I need to add things to listboxes and save the items so when the program closes they stay there next time it opens. I would prefer not using the settings to store the information.
Some more things I need for this. Saving them to a text file can't happen either. It needs to be saved in a way that it can not be edited outside of the program.
Sorry but its not possible. Anything that you save can be modified by another program.
You could sign the saved data and then detect that some other has modified the data, but you cannot prevent other programs from read/changing the data.
EDIT
DPAPI can be used to encrypt/decrypt the data. See Really simple encryption with C# and SymmetricAlgorithm
Set up SQL on a web server.
Save the info to your web server.
They can't modify data on a remote server, so I think a database is the way to go.
If you are the only person using that program... I mean... if you are the only one that knows what the program is doing, you could go for saving data in binary format into binary files. I doubt that someone looking at your files will say "Oh damn there is a .bin file in this directory! I have to find a way to discover how to read it and what's it's content!".
As long as you keep your program and its sources protected... I doubt someone will get something out of that content. You transform all your data into a Byte[], you compress it, you encrypt it and you write in a file. Bye bye.