Lua

Unzip a Text File Entry into a StringBuilder Using ZipEntry.UnzipToSb

See more Zip Examples

This example demonstrates how to use the ZipEntry.UnzipToSb method to inflate a text file entry directly into a StringBuilder object.

The ZIP entry is uncompressed entirely in memory and appended to the StringBuilder without creating a temporary file on disk.

This is useful when:

• Processing text files directly in memory
• Avoiding temporary filesystem files
• Reading configuration files, JSON, XML, CSV, or source code from ZIP archives
• Automatically converting line endings while inflating the text

The srcCharset argument specifies how the uncompressed bytes should be interpreted, such as:

• utf-8
• utf-16
• windows-1252

The lineEndingBehavior argument controls line-ending conversion:

• 0 — Leave line endings unchanged
• 1 — Convert all line endings to bare LF
• 2 — Convert all line endings to CRLF

Suppose the ZIP archive contains:

config/settings.json

The example inflates the JSON file directly into a StringBuilder.

Lua

local chilkat = require("chilkat")

local zip = chilkat.Zip.new()

-- Open an existing ZIP archive.
local success = zip:open_zip("qa_data/zips/configFiles.zip")
if not success then
    print(zip.last_error_text)
    return
end

-- Locate the JSON file entry within the ZIP archive.
local entry = chilkat.ZipEntry.new()

success = zip:entry_of("config/settings.json", entry)
if not success then
    print("ZIP entry not found.")
    zip:close_zip()
    return
end

-- ------------------------------------------------------------
-- Inflate the ZIP entry directly into a StringBuilder.
--
-- The uncompressed text is appended to the StringBuilder.
--
local sb = chilkat.StringBuilder.new()

-- Leave line endings unchanged.
local lineEndingBehavior = 0

-- Interpret the uncompressed bytes as UTF-8 text.
local srcCharset = "utf-8"

success = entry:unzip_to_sb(lineEndingBehavior, srcCharset, sb)
if not success then
    print(entry.last_error_text)
    return
end

print("Uncompressed text:")
print("")
print(sb:get_as_string())

zip:close_zip()

print("Done.")