在Objective-C中，我应该使用哪个压缩库来正确地组装一个有效的XLSX文件?

I am trying to modify an XLSX file programmatically using Objective-C.

我正在尝试使用Objective-C修改XLSX文件。

So far, I am only modifying the data on one of the sheets. The steps I am taking are as follows:

到目前为止，我只修改了其中一张表上的数据。我采取的步骤如下:

Copy the XLSX file to Documents folder
将XLSX文件复制到Documents文件夹
Unzip the XLSX container with keeping the directory structure
解压XLSX容器，保留目录结构
Parse the corresponding sheet XML file (sheet2.xml in my case)
解析相应的表XML文件(sheet2)。xml在我的例子中)
Add some rows
添加一些行
Rewrite the XML structure and save it
重写XML结构并保存它
Put the updated XML file back into the XLSX container
将更新后的XML文件放回XLSX容器中

However, the new XLSX file becomes corrupt. I am using GDataXML for XML parsing/writing and Objective-Zip for zipping/unzipping.

但是，新的XLSX文件会损坏。我使用GDataXML进行XML解析/编写，使用Objective-Zip进行压缩/解压缩。

I know that the XML file I have created is proper, because when I manually unzip and the re-zip the corrupt XLSX file, it opens without any errors. I have done this on both OS X (using Unarchiver) and Windows (using 7-Zip).

我知道我创建的XML文件是正确的，因为当我手动解压并重新解压损坏的XLSX文件时，它会在没有任何错误的情况下打开。我在OS X(使用Unarchiver)和Windows(使用7-Zip)上都这样做过。

The problem is either with the Objective-Zip library, or the way I use it. Below is how I implement the zipping method:

问题是要么是Objective-Zip库，要么是我使用它的方式。下面是我如何实现zipping方法:

ZipFile *zipFile = [[ZipFile alloc] initWithFileName:XLSXDocumentsFilePath mode:ZipFileModeAppend];
ZipWriteStream *stream= [zipFile writeFileInZipWithName:XLSX_WORKSHEET_XML_SUBPATH compressionLevel:ZipCompressionLevelNone];
[stream writeData:data];
[stream finishedWriting];
[zipFile close];

I also tried the other compressionLevel arguments available with no luck:

我还尝试了其他压缩级别的参数，但运气不好:

ZipCompressionLevelDefault
ZipCompressionLevelBest
ZipCompressionLevelFastest

My questions are:

我的问题是:

Which zipping library should I use to create a valid XLSX file programmatically?
我应该使用哪个压缩库来以编程方式创建一个有效的XLSX文件?
If Objective-Zip is suitable, what is wrong with my code?
如果Objective-Zip是合适的，我的代码有什么问题?

From an answer to another question, I found out that: "The OOXML format imposes that the only compression method permitted in the package is DEFLATE".

从对另一个问题的回答中，我发现:“OOXML格式强制要求在包中允许的惟一压缩方法是紧缩”。

Is it possible to force Objective-Zip to use DEFLATE? Or is there an open-source iOS zipping library that uses DEFLATE?

是否有可能强制Objective-Zip使用紧缩?或者有一个开源的iOS压缩库可以使用DEFLATE吗?

1 个解决方案

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I found the answer upon doing some research and also having a one to one correspondence with Objective-Zip's developer, flyingdolphinstudio.

我在做了一些研究后找到了答案，并与Objective-Zip的开发人员flyingdolphinstudio进行了一对一的通信。

First of all, Objective-Zip uses DEFLATE as the default compression method. I also confirmed this with the developer, who told me that using ZipCompressionLevelDefault, ZipCompressionLevelFastest or ZipCompressionLevelBest for the argument compressionLevel: will guarantee a DEFLATE compression.

首先，Objective-Zip使用DEFLATE作为默认的压缩方法。我也和开发人员确认了这一点，他们告诉我使用ZipCompressionLevelDefault、zipcompressionlevel最快或ZipCompressionLevelBest for the argument compressionLevel:将保证紧缩压缩。

So, the problem is coming from the mode: argument, which is ZipFileModeAppend in my case. It seems that MiniZip does not have a method to delete the files inside a zip file and that's why I am not overwriting the existing file, but adding a new one. To make it more clear, take a look at how my xl/worksheets folder look like after zipping it using Objective-Zip: 在Objective-C中，我应该使用哪个压缩库来正确地组装一个有效的XLSX文件?

因此，问题来自模式:参数，在我的例子中是ZipFileModeAppend。似乎MiniZip没有删除zip文件中的文件的方法，这就是为什么我没有覆盖现有文件，而是添加一个新的文件。为了让它更清晰，看看我的xl/worksheets文件夹在使用Objective-Zip压缩后的样子:

So, the only way to create a valid XLSX container is to create the zip file from scratch, by adding all the files and also keeping the directory/file structure intact.

因此，创建有效的XLSX容器的唯一方法是从头创建zip文件，方法是添加所有文件并保持目录/文件结构不变。

I hope this experience would help somebody out.

我希望这次经历能帮助别人。

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