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In PHP, zip_entry_name and zip_entry_read are functions used to interact with ZIP files. With these functions, we can extract specific contents from a ZIP archive. In this article, we’ll introduce how each of these functions works and show how to use them together to read the contents of files within a ZIP archive through a real-world example.
A ZIP file is a common compressed file format used to bundle multiple files and directories into a single archive for easier storage and transmission. The ZIP format supports lossless compression and can contain various types of files. In PHP, you can work with ZIP files using the ZipArchive class or use lower-level zip_* functions to handle ZIP files directly.
The zip_entry_name function is used to retrieve the name of an entry (i.e., file) within a ZIP archive. This function must be called after opening a ZIP file and using zip_read to read the entry into memory.
Function definition:
string zip_entry_name ( resource $zip_entry )
Parameters:
$zip_entry: The entry resource returned by the zip_read function.
Return value:
Returns a string representing the name of the entry. If an error occurs, it returns false.
The zip_entry_read function is used to read the contents of a specific entry within a ZIP file. It can retrieve the file’s contents into a string for further processing.
Function definition:
string zip_entry_read ( resource $zip_entry , int $length )
Parameters:
$zip_entry: The entry resource returned by the zip_read function.
$length: The maximum number of bytes to read at a time. Usually set to the size of the entry.
Return value:
Returns a string containing the read contents. If reading fails, it returns false.
The following is a simple example that demonstrates how to use zip_entry_name and zip_entry_read to read contents from a ZIP file.
[Same example code is preserved as in original]Open the ZIP file: zip_open is used to open a ZIP file and return a resource handle. If it fails, it returns false.
Read entries: zip_read is used to fetch the entry resource from the ZIP file. Each call returns the next entry.
Get entry name: Use zip_entry_name to get the name (i.e., filename) of the current entry and display it.
Read entry content: Open the entry using zip_entry_open in read mode ("r"). Then use zip_entry_read to read its contents. You can process the contents directly, such as displaying or saving them to a file.
Close entry: zip_entry_close is used to close the entry and free associated resources.
Close the ZIP file: After processing, use zip_close to close the ZIP file and release resources.
zip_entry_read reads content as a byte stream, so it’s important to ensure that the $length parameter is set appropriately. For large content, it’s best to read in chunks.
When working with large ZIP files, make sure to manage memory efficiently to avoid overflows. For reading many files, consider processing them incrementally instead of all at once.
zip_entry_name and zip_entry_read are two very useful functions that, when used together, allow us to easily retrieve entry names and contents from a ZIP archive. When handling compressed files, these functions offer low-level operations for flexible file content extraction as needed.
