If we restart the server and upload a file to the server, the file will be uploaded to the created directory instead of the root directory. We can also configure the maximum upload size of the file. This is important because if the file is too large for the server, then the site may crash. So, we need to always limit the upload size of the file according to our server. To configure the maximum file size, we need to set the app. For example, if we want to limit the maximum size of the file to 1 Mb, we need to add the following line of code in our program.
After setting the maximum file size of the file in our python program, if we upload a file having a size of more than 1 Mb, then we will get the error as shown in the below image. While building a file uploader using Flask, we can also configure the file extensions that we want to upload. To configure the allowed file extensions, we need to create a list of allowed extensions and check the uploaded file extension in the list.
The below code shows a practical illustration of the method. In the above code, we create a function that will check the uploaded file extension and compare it with the allowed extensions. Till now, we have seen how to upload a single file to our server.
But sometimes, we also want to upload multiple files to the server. See the below code for illustration. After creating the Html form, we need to make some changes to our Flask application file.
First, copy the following Python code into your Flask app file. In the above code, we use python for loop to iterate over the list of files and then save each file one by one. We can choose multiple files now and upload them at once to the server.
We have seen how to upload files using Flask, but sometimes we also want to serve a file to the user. First, create an HTML template in the templates folder, named the file download.
Now, we need to create our app. In our app. Then, copy and paste the following code in the app. After copying the above code, run the code by typing the command python app. If everything works fine and the server starts without any problem, we have created our file downloader.
If you click the download button present in the URL, then the file will start downloading. For the above code to work properly, we need a file with the name sample.
In this tutorial, we learned to create a file uploader and file downloader using the Flask library. Notice in the above template file I am using Flask EL Expression language to evaluate the link endpoint.
Now navigate to the project root directory from command line tool and execute the command python main. If you want to change the port then you can change the line app.
Any way to clear the cache from Flask? Your email address will not be published. Roy Tutorials Technical… Theoretical… Practical…. Introduction Here I am going to show a simple example on how to download a file from web application using Python Flask. Prerequisites Python 3. Project Directory First step is to create a project root directory under which I will put all the required files for the project.
How should I structure this program? I would prefer to work on the files wihthout saving them anywhere but if I have to save them to the PythonAnywhere directory, I could. How can I do that? PythonAnywhere dev here. This is a good question about Flask and web development in general rather than specific to our system, so I'll try to give a generic answer without anything specific to us There are a few things that I'd need to know to give a definitive answer to your question, so I'll start by listing the assumptions I'm making -- leave me a comment if I'm wrong with any of them and I'll update the answer appropriately.
If both of those are the case, then the best way to structure your Flask app would be to handle everything inside Flask. There's a live version of this app on PythonAnywhere here.
If you don't add the content type, FF If you don't add Cache-Control your result may get cached, and if you serve active content this is not what you want.
If you use must-revalidate with no age, it will effectively serve as no-cache - see here and here for an explanation. Stack Overflow for Teams — Collaborate and share knowledge with a private group.
Create a free Team What is Teams? Collectives on Stack Overflow. Learn more. First we should be able to read pdf file, for that we would use PyPDF2 module. I simply reduced the height of the page which cuts the watermark from the image. Once height of image is reduced I add the modified pdf page to another pdf which I would expose to user for download.
Once the uploaded file is processed, we send it to user i. This is a secure way to quickly expose static files from an upload folder or something similar. Your site would have a limit on file size to process.
Now the Flask app is complete with all the required functionalities i.
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