Lua Requires Chilkat v11.0.0+

Find a ZIP Entry by EntryID Using EntryById

See more Zip Examples

This example demonstrates how to use the EntryById method to retrieve a ZIP entry using its unique EntryID.

Each ZipEntry object has an EntryID property that uniquely identifies the entry within the currently open ZIP object.

This is useful when:

• An application stores EntryID values for later use
• ZIP entries need to be retrieved without searching by filename
• Multiple entries may have similar names or paths

The example:

• Opens a ZIP archive
• Retrieves an entry using EntryAt
• Saves the entry's EntryID
• Uses EntryById to retrieve the same entry later

Lua

local chilkat = require("chilkat")

-- Open an existing ZIP archive.
local zip = chilkat.Zip.new()

local success = zip:open_zip("example.zip")
if not success then
    print(zip.last_error_text)
    return
end

-- Retrieve the first entry in the ZIP archive.
local entry = chilkat.ZipEntry.new()

success = zip:entry_at(0, entry)
if not success then
    print(zip.last_error_text)
    return
end

print("Original entry:")
print("  FileName: " .. entry.file_name)
print("  EntryID: " .. entry.entry_id)
print("")

-- Save the EntryID for later use.
local entryId = entry.entry_id

-- Create another ZipEntry object.
local entry2 = chilkat.ZipEntry.new()

-- Retrieve the same entry using EntryById.
success = zip:entry_by_id(entryId, entry2)
if not success then
    print(zip.last_error_text)
    return
end

print("Entry retrieved by EntryID:")
print("  FileName: " .. entry2.file_name)
print("  EntryID: " .. entry2.entry_id)
print("")

-- The filenames and EntryID values should match.
zip:close_zip()

print("Done.")