给定一个字符串，如何使用gzip将其压缩到内存中？我正在使用Lua。
这听起来像是一个简单的问题，但有大量的库。到目前为止，我尝试的所有内容要么死了，要么只能生成 zlib 压缩字符串。在我的用例中，我需要 gzip 压缩，正如接收器所期望的那样。
作为测试，如果将压缩字符串转储到文件中，zcat应该能够解压缩它。
我正在使用OpenResty，所以任何Lua库都应该没问题。
(到目前为止，我工作的唯一解决方案是将字符串转储到文件中，调用os.execute("gzip /tmp/example.txt")并读回它。不幸的是，这不是一个实用的解决方案。
事实证明，zlib离gzip不远了。不同之处在于 gzip 有一个额外的标头。
要获取此标头，您可以使用如下所示的lua-zlib：
local zlib = require "zlib"
-- input: string
-- output: string compressed with gzip
function compress(str)
local level = 5
local windowSize = 15+16
return zlib.deflate(level, windowSize)(str, "finish")
end
解释：
- 放气的第二个参数是窗口大小。它确保写入 gzip 标头。如果省略该参数，则会得到一个 zlib 压缩字符串。
- 级别是 gzip 压缩级别(1=最差到 9=最好(
以下是放气的文档(来源：lua-zlib文档(：
函数流 = zlib.deflate([ int compression_level ]， [ int window_size ](
If no compression_level is provided uses Z_DEFAULT_COMPRESSION (6),
compression level is a number from 1-9 where zlib.BEST_SPEED is 1
and zlib.BEST_COMPRESSION is 9.
Returns a "stream" function that compresses (or deflates) all
strings passed in. Specifically, use it as such:
string deflated, bool eof, int bytes_in, int bytes_out =
stream(string input [, 'sync' | 'full' | 'finish'])
Takes input and deflates and returns a portion of it,
optionally forcing a flush.
A 'sync' flush will force all pending output to be flushed to
the return value and the output is aligned on a byte boundary,
so that the decompressor can get all input data available so
far. Flushing may degrade compression for some compression
algorithms and so it should be used only when necessary.
A 'full' flush will flush all output as with 'sync', and the
compression state is reset so that decompression can restart
from this point if previous compressed data has been damaged
or if random access is desired. Using Z_FULL_FLUSH too often
can seriously degrade the compression.
A 'finish' flush will force all pending output to be processed
and results in the stream become unusable. Any future
attempts to print anything other than the empty string will
result in an error that begins with IllegalState.
The eof result is true if 'finish' was specified, otherwise
it is false.
The bytes_in is how many bytes of input have been passed to
stream, and bytes_out is the number of bytes returned in
deflated string chunks.