尝试从 Python (w/PyObjC) 写入二进制 plist 格式，以便由 Cocoa Touch 获取和读取
我正在尝试向我的 iPhone 应用程序提供搜索结果的属性列表。该服务器是一个原型，用 Python 编写。
首先我找到了Python内置的plistlib，非常棒。我想尝试一下“键入即搜索”，所以我需要它尽可能小，而 xml 太大了。二进制 plist 格式似乎是一个不错的选择。不幸的是 plistlib 不处理二进制文件，所以直接使用 PyObjC。
（Segue：对于如何完成实时搜索的任何其他想法，我都非常开放。我已经尽可能地减少了数据，包括仅显示足够的结果来填充 iPhone 键盘向上的窗口，即 5。）
不幸的是，尽管我了解 Python 并且对 Cocoa 的了解也相当不错，但我仍然不懂 PyObjC。
这就是我想要做的 Cocoa 等效项：
NSArray *plist = [NSArray arrayWithContentsOfFile:read_path];
NSError *err;
NSData *data = [NSPropertyListSerialization dataWithPropertyList:plist
format:NSPropertyListBinaryFormat_v1_0
options:0 // docs say this must be 0, go figure
error:&err];
[data writeToFile:write_path atomically:YES];
我认为我应该能够做这样的事情，但是 dataWithPropertyList 不在 NSPropertyListSerialization 对象 dir() 列表中。我还应该将列表转换为 NSArray。我尝试了 PyObjC 文档，但它与我的实际工作太不相干了，所以我想我也应该尝试一下 SO SOS。
from Cocoa import NSArray, NSData, NSPropertyListSerialization, NSPropertyListBinaryFormat_v1_0
plist = [dict(key1='val', key2='val2'), dict(key1='val', key2='val2')]
NSPropertyListSerialization.dataWithPropertyList_format_options_error(plist,
NSPropertyListBinaryFormat_v1_0,
?,
?)
这就是我在 iPhone 端的 plist 中阅读的方式。
NSData *data = [NSData dataWithContentsOfURL:url];
NSPropertyListFormat format;
NSString *err;
id it = [NSPropertyListSerialization
propertyListFromData:data
mutabilityOption:0
format:&format
errorDescription:&err];
很高兴澄清其中是否有任何意义。
I'm trying to serve a property list of search results to my iPhone app. The server is a prototype, written in Python.
First I found Python's built-in plistlib, which is awesome. I want to give search-as-you-type a shot, so I need it to be as small as possible, and xml was too big. The binary plist format seems like a good choice. Unfortunately plistlib doesn't do binary files, so step right up PyObjC.
(Segue: I'm very open to any other thoughts on how to accomplish live search. I already pared down the data as much as possible, including only displaying enough results to fill the window with the iPhone keyboard up, which is 5.)
Unfortunately, although I know Python and am getting pretty decent with Cocoa, I still don't get PyObjC.
This is the Cocoa equivalent of what I want to do:
NSArray *plist = [NSArray arrayWithContentsOfFile:read_path];
NSError *err;
NSData *data = [NSPropertyListSerialization dataWithPropertyList:plist
format:NSPropertyListBinaryFormat_v1_0
options:0 // docs say this must be 0, go figure
error:&err];
[data writeToFile:write_path atomically:YES];
I thought I should be able to do something like this, but dataWithPropertyList isn't in the NSPropertyListSerialization objects dir() listing. I should also probably convert the list to NSArray. I tried the PyObjC docs, but it's so tangential to my real work that I thought I'd try an SO SOS, too.
from Cocoa import NSArray, NSData, NSPropertyListSerialization, NSPropertyListBinaryFormat_v1_0
plist = [dict(key1='val', key2='val2'), dict(key1='val', key2='val2')]
NSPropertyListSerialization.dataWithPropertyList_format_options_error(plist,
NSPropertyListBinaryFormat_v1_0,
?,
?)
This is how I'm reading in the plist on the iPhone side.
NSData *data = [NSData dataWithContentsOfURL:url];
NSPropertyListFormat format;
NSString *err;
id it = [NSPropertyListSerialization
propertyListFromData:data
mutabilityOption:0
format:&format
errorDescription:&err];
Happy to clarify if any of this doesn't make sense.
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我相信正确的函数名称是
因为结尾
:。（顺便说一句，如果对象始终是数组或字典，
-writeToFile:atomically:将已经写入 plist（作为 XML 格式）。）I believe the correct function name is
because of the ending
:.(BTW, if the object is always an array or dictionary,
-writeToFile:atomically:will write the plist (as XML format) already.)正如 KennyTM 所说，您缺少方法名称中的尾部下划线。在 PyObjC 中，您需要获取 Objective-C 选择器名称 (
dataWithPropertyList:format:options:error:) 并将所有冒号替换为下划线（也不要忘记最后一个冒号！）。这将为您提供dataWithPropertyList_format_options_error_（请注意结尾的下划线）。另外，对于error参数，您可以只使用None。这使您的代码看起来像这样：如果您测试生成的文件，您将看到它是一个二进制 PList 文件，如所需：
As KennyTM said, you're missing the trailing underscore in the method name. In PyObjC you need to take the Objective-C selector name (
dataWithPropertyList:format:options:error:) and replace all of the colons with underscores (don't forget the last colon, too!). That gives youdataWithPropertyList_format_options_error_(note the trailing underscore). Also, for theerrorparameter, you can just useNone. That makes your code look like this:If you test the resulting file, you'll see that it's a Binary PList file, as desired: