Below are some common problems encountered when working with uploading files and their possible solutions. The following error indicates that the uploaded file exceeds the server's configured content length:.
A connection error and a reset server connection probably indicates that the uploaded file exceeds Kestrel's maximum request body size. For more information, see the Kestrel maximum request body size section. Kestrel client connection limits may also require adjustment.
Also confirm that the upload naming in form data matches the app's naming. The examples in this topic rely upon MemoryStream to hold the uploaded file's content. The size limit of a MemoryStream is int.
If the app's file upload scenario requires holding file content larger than 50 MB, use an alternative approach that doesn't rely upon a single MemoryStream for holding an uploaded file's content. Data storage service for example, Azure Blob Storage. The following example demonstrates how to use JavaScript to stream a file to a controller action. MaxRequestBodySize in Startup. For more information, see Host ASP. Skip to main content. This browser is no longer supported. Download Microsoft Edge More info.
Contents Exit focus mode. Upload files in ASP. Is this page helpful? Please rate your experience Yes No. Any additional feedback? View or download sample code how to download Security considerations Use caution when providing users with the ability to upload files to a server.
Attackers may attempt to: Execute denial of service attacks. Upload viruses or malware. Compromise networks and servers in other ways.
Security steps that reduce the likelihood of a successful attack are: Upload files to a dedicated file upload area, preferably to a non-system drive. A dedicated location makes it easier to impose security restrictions on uploaded files. Disable execute permissions on the file upload location. Don't use a file name provided by the user or the untrusted file name of the uploaded file. Allow only approved file extensions for the app's design specification.
Check the size of an uploaded file. Set a maximum size limit to prevent large uploads. Warning Uploading malicious code to a system is frequently the first step to executing code that can: Completely gain control of a system. Overload a system with the result that the system crashes.
Compromise user or system data. Apply graffiti to a public UI. For information on reducing the attack surface area when accepting files from users, see the following resources: Unrestricted File Upload Azure Security: Ensure appropriate controls are in place when accepting files from users. Note Any single buffered file exceeding 64 KB is moved from memory to a temp file on disk. How much do they charge for the service? Most are free, but watch out for advertising.
How long will they keep uploaded files? Is their privacy policy acceptable? Yes No. Not Helpful 16 Helpful How do I change the format on my document if where I need to send it does not have this format option? Click "Save as" to reveal different formats you may save the file as. Not Helpful 5 Helpful If you own your own website and you don't have an uploading interface like many host services do, you can put your files on your server by using FTP.
Contact your host provider for the account details. Not Helpful 6 Helpful 6. You will have to scan the printed page with a printer and then save it as a PDF.
Not Helpful 1 Helpful Include your email address to get a message when this question is answered. This option is at the bottom of the window. Enter the address for the FTP server. It's at the bottom of the window. Set your username for the FTP server. If the FTP server requires usernames in order to connect, uncheck the "Log on anonymously" box and enter the username you want to use in the text field.
If the server doesn't require a username, it's a good idea to keep the "Log on anonymously" box checked. Enter a name for the FTP server. Type your preferred name for the server into the text box in the middle of the window. The name is simply for your reference to help you find it on your computer. Click Next , then click Finish. Both options are at the bottom of their respective pages in the FTP setup window. This will complete the setup process and attempt to open your FTP server.
You may have to wait a minute or so before the FTP server folder will open. You can also just double-click the server's folder in This PC to open it. Enter your password if prompted. If you are connecting to a secured FTP, you'll be asked for your user password when you first connect. Enter the password when prompted or the connection won't work.
Upload files to the FTP server. Keep in mind that this only works for servers for which you have permission to upload: Find a file that you want to upload. Method 3. Click Go. It's at the top of your Mac's screen.
Clicking it prompts a drop-down menu. Click Connect to Server…. You'll find this option near the bottom of the drop-down menu. Enter the server's address. In the "Server Address" text box, type in the address for the server to which you want to connect.
Add the server to your favorites. This is optional, but recommended if you plan on connecting often to the server. Click Connect. It's a blue button in the lower-right side of the window. Enter a username and password if prompted. You will be prompted for your username and password if the FTP requires it. If not asked for a username or password, you can choose to log in as a Guest anonymously.
Keep in mind that this only works for servers for which you have permission to upload: Find a file on your Mac. Open the FTP window. Method 4. Download the FTPManager app. Open FTPManager. It's in the top-right corner of the screen. Tap FTP. This option is near the top of the page. Doing so opens a form for a new FTP connection.
Enter your FTP server's address. Add a username and password. Tap Save. In order to run the server, you must have Node. Open Terminal and type the following command:. There is a space character after the cd command. Then switch to Finder, and drag and drop the Server directory to terminal and press the Return key:. You can also verify that if you paste that address in a new tab in your browser.
Note: If you are already running another server at port , edit the index. Then restart the server with the node index. However, for the sake of the tutorial, localhost has been whitelisted in the Info. The first thing we need to take care of is how files are going to be represented in the RestManager class.
For any file that is about to be uploaded, we need to have the following data available at the time of the HTTP body preparation:. Open the RestManager. You will find the following empty extension:. Inside this extension, add the following structure:. The four properties will keep the data described earlier. We can make the initialization of a FileInfo object more friendly if we add the following custom initializer:.
Specifying the URL of the file will be enough. File contents will be read in the above initializer. Remember that a boundary must be unique and definitely not an ordinary string that could be potentially found in the actual data that will be uploaded. The fastest way to get a random string is to generate a UUID value:.
It will be a concatenation of 20 dashes at the beginning and the transformed UUID value:. As an alternative to the above we can create a mechanism which will pick random characters from a collection of available characters, and using them to form a string which will be appended to the boundary string.
However, the second line of code requires from us to search for an ASCII table online and then locate the position of the characters we are interested in into the table. Data struct provides several initializers for creating a data object and there is one among them that accepts a sequence as an argument, exactly as we do in the Data sequenceOfRanges expression.
From that data object, we can create the following string which is assigned to the toString constant:. At first we initialize a string value called randomString. Then, we create a loop that will be executed 20 times. In it, we pick a random character from the toString string using the randomElement method, and we generate a new String value String toString.
This new String value is appended to the randomString. Note that is safe to force unwrap the value of the randomElement method, as it returns nil only in cases of empty collections. Use the implementation you prefer the most. At the end of the day, both approaches are going to work equally well. These two dashes are not included in the dashes of the boundary string we generated in both approaches here.
This string will be provided as-is to the request as a request header along with the content type and server will try to locate it after the two dashes prefix. Also, a boundary string can exist with no dashes at all; we just add them to minimize the possibility to find similar string in the uploaded data.
As you will see later, the two dashes prefix will be manually appended whenever necessary.
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