Скачать или смотреть How to Use libcurl to Retrieve File Size from an FTP Server

Discover how to efficiently use `libcurl` to get the file size on an FTP server without having to upload or download files.
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This video is based on the question https://stackoverflow.com/q/64057867/ asked by the user 'suihe dolood' ( https://stackoverflow.com/u/11344284/ ) and on the answer https://stackoverflow.com/a/64059169/ provided by the user 'Daniel Stenberg' ( https://stackoverflow.com/u/93747/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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Using libcurl to Get File Size on an FTP Server

When handling file transfers to remote servers, especially in an FTP environment, it’s crucial to not only upload your files but also to have access to metadata about those files. This can often present challenges, especially if you need to know the size of a file without actually downloading it. Thankfully, using libcurl, you can retrieve this information seamlessly.

The Challenge: Accessing File Metadata

If you're working with remote servers, particularly for uploading files, it’s common to run into situations where you need to know specific details about those files, like their size. However, typical FTP operations often involve the complications of uploading or downloading the files themselves, which can be inefficient and time-consuming. Your goal is to gather information without unnecessary data transfer.

The Solution: Using libcurl with CURLOPT_NOBODY

What is libcurl?

libcurl is a free and easy-to-use client-side URL transfer library that supports various protocols, including FTP. Using libcurl, you can perform a multitude of operations, making it a versatile tool for anyone dealing with file transfers and network communications.

Getting the File Size Without Downloading

To get the file size of a file on an FTP server while avoiding the actual download process, you can utilize the CURLOPT_NOBODY option. Here’s how it works:

Set CURLOPT_NOBODY: This option, when set to 1L, tells libcurl to not include the body in the response.

This means you will only receive metadata about the file, which includes the file size.

Make the Request: By making a request to the file URL with CURLOPT_NOBODY, you will get the necessary information without receiving the actual file contents.

Implementing the Solution: Example Code

Here’s a simple example of how you can implement this in your code:

[[See Video to Reveal this Text or Code Snippet]]

Key Takeaways

Efficiency: Using CURLOPT_NOBODY allows you to gather essential file information without the overhead of transferring data.

Simplicity: The solution is straightforward and integrates easily into your existing projects or workflows.

Versatility: This technique can be applied to any file hosted on an FTP server.

Conclusion

By leveraging libcurl with the CURLOPT_NOBODY option, you can efficiently obtain file size information from an FTP server without the needless hassle of file transfers. This technique not only saves time and bandwidth but also streamlines your file management processes. Whether you’re uploading files or just need to check file details, libcurl offers the flexibility you need to make your task much more manageable.

Feel free to integrate the solution into your work and enjoy the efficiency that libcurl provides!