如何将文件转换为 Objective C 中的十六进制表示法？
我正在尝试通过 iOS / Objective C 使用 Tumblr API 对 png 进行 urlencode 上传。这相对令人难以置信，但 Tumblr API 只接受在一个照片集中上传多张照片的“urlencoded 二进制数据”，并且不会接受通常的简单形式数据帖子。我有一个由 Tumblr 提供的 有效的 Python 示例。它需要一个图像/二进制文件并将其读取为以下（我猜是十六进制）格式：
'\x89PNG\r\n\x1a\n\x00\x00\x00\rIHDR\x00\x00\x00 \x00\x00\x00\x1d\x08\x06\x00\x00\x00\xcb\x9en\x87\x00\x00\x01\xc9IDATH\r\xc5\x971K\x03A\x10\x85s\nB \x10\xb0\n\xa4\xb2J\x95* \x08\x82\x95\xbfA\x10\xfc\x01V\xb6\x82\x95?\xc0J\x10\x04[[\xc16U@\xb0\x8d`/(\x8a\x82\x08Z\t\x12\x89\xdf$\xd9p\x9c\xae\xfb&\x9c8\xf0\xd8\xbd\xdb\xb7o^\xe6\x96\xb9K6\x1c\x0e+\xb3D\x96e\xf3\xeck\xb3\xffj\x96\xfda\xcf\\\x98\xa8#\x89\xdb\xe0\x1c\xfe\x00\xf4\x99\x0f@\x17\xec\x80\xba\xaa3\xe5Y\x05\x14\xb0\xa1\x06\x0e\xc0=\xb0\xb2\xfd\x84\x17\xee\xaf(z\x81#%72\xb1\x1bIZ4r\x03\xaf\x16\x12\xa4F\xc9\x00\x82\xf6\xbcM\xb8\x98,v\xbd\x9fJ\x1c\xd6\xd53\xd0 \xf9\x12Pc]%\xaa\x06\x9e\x11\xfcTE\xe1\xd9y\x91B2@\xb9>P{\x90\x14\xc7$\xe3K!\x19\x98(Y\x15\xd4xR\x89\x1e\x03\xef\xaa(\xbc7\x95\xeb1\xd0RE\xe1-\xab\\\x8f\x01\xcf\x19\xb8\xfb\x0b\x03\x9e\x9e\x7f\xad\x1a\x90\x1a\x915\rb\x15\xdc\x82X\xf3\t\xf7\x1f\xe1tB\xa3I\x8d\xb2\x81\x89\x89=\xc1\xc0v*i~\xdds\x06\xc8]QJ\xabpLk\x1cy7\xa99;\x16@\x1f\x84r\x17\xc7K\xe3\xa4t\xf2\xeb\xde\n\xd8;\xe1\xb7\x13n\xcd\xca^\\z\xe4\xdd\xa4\xe6\xa8^\x80\xe2\xaf.^\x9f\xa4t\xf2\xeb\xd2!$i\x13\x1c\n\xc9\x83\x993\xb8\xad|\xa2\xd8<j\x00\x01{\xde\x9b\xa0\x0b\x82\xb0w\xec\xb1w\x0bTe\x03\x90;\xc0~\xad}^y\x13\xc6\xf8\xafh\x1d\x81o\xfdaZ\x01\x167\x80\xf2\x8ccI\xd4\xfb=\xf2\xac\x85\x8a\x8c\x0cp\xe3\x14\xa8\x02e\xf1\x8e\xcd\x84\x85}>\x95%\xea\xd5iX\x1f\xf0|\xeb\x99\xe12\xa3i\x06\xfc\x7f&\xca\xb30\xaa\xc0byzn\xa5\xbaU\xe0?\rT\xbf\x00\x87\x89 \xa8s3+7\x00\x00\x00\x00IEND\xaeB`\x82'
然后它会进行一些 url 编码来创建它：
89PNG%250D%250A%251A%250A%2500%2500%2500%250DIHDR%2500%2500%2500%2520%2500%2500%2500%251D%2508%2506%2500%2500%2500%25CB%259En%2587%2500%2500%2501%25C9IDATH%250D%25C5%25971K%2503A%2510%2585s%250AB%2520%2510%25B0%250A%25A4%25B2J%2595%252A%2520%2508%2582%2595%25BFA%2510%25FC%2501V%25B6%2582%2595%253F%25C0J%2510%2504%255B%255B%25C16U%2540%25B0%258D%2560%252F%2528%258A%2582%2508Z%2509%2512%2589%25DF%2524%25D9p%259C%25AE%25FB%2526%259C8%25F0%25D8%25BD%25DB%25B7o%255E%25E6%2596%25B9K6%251C%250E%252B%25B3D%2596e%25F3%25ECk%25B3%25FFj%2596%25FDa%25CF%255C%2598%25A8%2523%2589%25DB%25E0%251C%25FE%2500%25F4%2599%250F%2540%2517%25EC%2580%25BA%25AA3%25E5Y%2505%2514%25B0%25A1%2506%250E%25C0%253D%25B0%25B2%25FD%2584%2517%25EE%25AF%2528z%2581%2523%252572%25B1%251BIZ4r%2503%25AF%2516%2512%25A4F%25C9%2500%2582%25F6%25BCM%25B8%2598%252Cv%25BD%259FJ%251C%25D6%25D53%25D0%2520%25F9%2512Pc%255D%2525%25AA%2506%259E%2511%25FCTE%25E1%25D9y%2591B2%2540%25B9%253EP%257B%2590%2514%25C7%2524%25E3K%2521%2519%2598%2528Y%2515%25D4xR%2589%251E%2503%25EF%25AA%2528%25BC7%2595%25EB1%25D0RE%25E1-%25AB%255C%258F%2501%25CF%2519%25B8%25FB%250B%2503%259E%259E%257F%25AD%251A%2590%251A%25915%250Db%2515%25DC%2582X%25F3%2509%25F7%251F%25E1tB%25A3I%258D%25B2%2581%2589%2589%253D%25C1%25C0v%252Ai~%25DDs%2506%25C8%255DQJ%25ABpLk%251Cy7%25A99%253B%2516%2540%251F%2584r%2517%25C7K%25E3%25A4t%25F2%25EB%25DE%250A%25D8%253B%25E1%25B7%2513n%25CD%25CA%255E%255Cz%25E4%25DD%25A4%25E6%25A8%255E%2580%25E2%25AF.%255E%259F%25A4t%25F2%25EB%25D2%2521%2524i%2513%251C%250A%25C9%2583%25993%25B8%25AD%257C%25A2%25D8%253Cj%2500%2501%257B%25DE%259B%25A0%250B%2582%25B0w%25EC%25B1w%250BTe%2503%2590%253B%25C0~%25AD%257D%255Ey%2513%25C6%25F8%25AFh%251D%2581o%25FDaZ%2501%25167%2580%25F2%258CcI%25D4%25FB%253D%25F2%25AC%2585%258A%258C%250Cp%25E3%2514%25A8%2502e%25F1%258E%25CD%2584%2585%257D%253E%2595%2525%25EA%25D5iX%251F%25F0%257C%25EB%2599%25E12%25A3i%2506%25FC%257F%2526%25CA%25B30%25AA%25C0byzn%25A5%25BAU%25E0%253F%250DT%25BF%2500%2587%2589%2520%25A8s3%252B7%2500%2500%2500%2500IEND%25AEB%2560%2582
然后它会发布上述数据以及其他一些数据。我怎样才能在 Objective C 中做到这一点——即获取 89PNG... 字符串？我尝试使用以下方法读取图像：
NSData *data = [NSData dataWithContentsOfFile:[[NSBundle mainBundle] pathForResource:@"filename" ofType:@"png"]];
然后使用以下方法转换为十六进制字符串：
NSString *dataString = [data description];
dataString = [[dataString stringByTrimmingCharactersInSet:[NSCharacterSet characterSetWithCharactersInString:@"<>"]] stringByReplacingOccurrencesOfString:@" " withString:@""];
然后我得到了看起来很接近的东西：
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
但不幸的是还不够接近。接下来我该怎么做才能将此字符串转换为 89PNG... 字符串？
I'm trying to urlencode a png for upload using the Tumblr API via iOS / Objective C. This is relatively unbelievable, but the Tumblr API will only accept 'urlencoded binary data' for multiple photo uploads in one photoset, and won't accept the usual simple form data posts. I have a working Python example provided by Tumblr. It takes an image / binary file and reads it to this (I guess hexadecimal) format:
'\x89PNG\r\n\x1a\n\x00\x00\x00\rIHDR\x00\x00\x00 \x00\x00\x00\x1d\x08\x06\x00\x00\x00\xcb\x9en\x87\x00\x00\x01\xc9IDATH\r\xc5\x971K\x03A\x10\x85s\nB \x10\xb0\n\xa4\xb2J\x95* \x08\x82\x95\xbfA\x10\xfc\x01V\xb6\x82\x95?\xc0J\x10\x04[[\xc16U@\xb0\x8d`/(\x8a\x82\x08Z\t\x12\x89\xdf$\xd9p\x9c\xae\xfb&\x9c8\xf0\xd8\xbd\xdb\xb7o^\xe6\x96\xb9K6\x1c\x0e+\xb3D\x96e\xf3\xeck\xb3\xffj\x96\xfda\xcf\\\x98\xa8#\x89\xdb\xe0\x1c\xfe\x00\xf4\x99\x0f@\x17\xec\x80\xba\xaa3\xe5Y\x05\x14\xb0\xa1\x06\x0e\xc0=\xb0\xb2\xfd\x84\x17\xee\xaf(z\x81#%72\xb1\x1bIZ4r\x03\xaf\x16\x12\xa4F\xc9\x00\x82\xf6\xbcM\xb8\x98,v\xbd\x9fJ\x1c\xd6\xd53\xd0 \xf9\x12Pc]%\xaa\x06\x9e\x11\xfcTE\xe1\xd9y\x91B2@\xb9>P{\x90\x14\xc7$\xe3K!\x19\x98(Y\x15\xd4xR\x89\x1e\x03\xef\xaa(\xbc7\x95\xeb1\xd0RE\xe1-\xab\\\x8f\x01\xcf\x19\xb8\xfb\x0b\x03\x9e\x9e\x7f\xad\x1a\x90\x1a\x915\rb\x15\xdc\x82X\xf3\t\xf7\x1f\xe1tB\xa3I\x8d\xb2\x81\x89\x89=\xc1\xc0v*i~\xdds\x06\xc8]QJ\xabpLk\x1cy7\xa99;\x16@\x1f\x84r\x17\xc7K\xe3\xa4t\xf2\xeb\xde\n\xd8;\xe1\xb7\x13n\xcd\xca^\\z\xe4\xdd\xa4\xe6\xa8^\x80\xe2\xaf.^\x9f\xa4t\xf2\xeb\xd2!$i\x13\x1c\n\xc9\x83\x993\xb8\xad|\xa2\xd8<j\x00\x01{\xde\x9b\xa0\x0b\x82\xb0w\xec\xb1w\x0bTe\x03\x90;\xc0~\xad}^y\x13\xc6\xf8\xafh\x1d\x81o\xfdaZ\x01\x167\x80\xf2\x8ccI\xd4\xfb=\xf2\xac\x85\x8a\x8c\x0cp\xe3\x14\xa8\x02e\xf1\x8e\xcd\x84\x85}>\x95%\xea\xd5iX\x1f\xf0|\xeb\x99\xe12\xa3i\x06\xfc\x7f&\xca\xb30\xaa\xc0byzn\xa5\xbaU\xe0?\rT\xbf\x00\x87\x89 \xa8s3+7\x00\x00\x00\x00IEND\xaeB`\x82'
Then it does some url encoding to create this:
89PNG%250D%250A%251A%250A%2500%2500%2500%250DIHDR%2500%2500%2500%2520%2500%2500%2500%251D%2508%2506%2500%2500%2500%25CB%259En%2587%2500%2500%2501%25C9IDATH%250D%25C5%25971K%2503A%2510%2585s%250AB%2520%2510%25B0%250A%25A4%25B2J%2595%252A%2520%2508%2582%2595%25BFA%2510%25FC%2501V%25B6%2582%2595%253F%25C0J%2510%2504%255B%255B%25C16U%2540%25B0%258D%2560%252F%2528%258A%2582%2508Z%2509%2512%2589%25DF%2524%25D9p%259C%25AE%25FB%2526%259C8%25F0%25D8%25BD%25DB%25B7o%255E%25E6%2596%25B9K6%251C%250E%252B%25B3D%2596e%25F3%25ECk%25B3%25FFj%2596%25FDa%25CF%255C%2598%25A8%2523%2589%25DB%25E0%251C%25FE%2500%25F4%2599%250F%2540%2517%25EC%2580%25BA%25AA3%25E5Y%2505%2514%25B0%25A1%2506%250E%25C0%253D%25B0%25B2%25FD%2584%2517%25EE%25AF%2528z%2581%2523%252572%25B1%251BIZ4r%2503%25AF%2516%2512%25A4F%25C9%2500%2582%25F6%25BCM%25B8%2598%252Cv%25BD%259FJ%251C%25D6%25D53%25D0%2520%25F9%2512Pc%255D%2525%25AA%2506%259E%2511%25FCTE%25E1%25D9y%2591B2%2540%25B9%253EP%257B%2590%2514%25C7%2524%25E3K%2521%2519%2598%2528Y%2515%25D4xR%2589%251E%2503%25EF%25AA%2528%25BC7%2595%25EB1%25D0RE%25E1-%25AB%255C%258F%2501%25CF%2519%25B8%25FB%250B%2503%259E%259E%257F%25AD%251A%2590%251A%25915%250Db%2515%25DC%2582X%25F3%2509%25F7%251F%25E1tB%25A3I%258D%25B2%2581%2589%2589%253D%25C1%25C0v%252Ai~%25DDs%2506%25C8%255DQJ%25ABpLk%251Cy7%25A99%253B%2516%2540%251F%2584r%2517%25C7K%25E3%25A4t%25F2%25EB%25DE%250A%25D8%253B%25E1%25B7%2513n%25CD%25CA%255E%255Cz%25E4%25DD%25A4%25E6%25A8%255E%2580%25E2%25AF.%255E%259F%25A4t%25F2%25EB%25D2%2521%2524i%2513%251C%250A%25C9%2583%25993%25B8%25AD%257C%25A2%25D8%253Cj%2500%2501%257B%25DE%259B%25A0%250B%2582%25B0w%25EC%25B1w%250BTe%2503%2590%253B%25C0~%25AD%257D%255Ey%2513%25C6%25F8%25AFh%251D%2581o%25FDaZ%2501%25167%2580%25F2%258CcI%25D4%25FB%253D%25F2%25AC%2585%258A%258C%250Cp%25E3%2514%25A8%2502e%25F1%258E%25CD%2584%2585%257D%253E%2595%2525%25EA%25D5iX%251F%25F0%257C%25EB%2599%25E12%25A3i%2506%25FC%257F%2526%25CA%25B30%25AA%25C0byzn%25A5%25BAU%25E0%253F%250DT%25BF%2500%2587%2589%2520%25A8s3%252B7%2500%2500%2500%2500IEND%25AEB%2560%2582
Then it POSTs the above data along with some other pieces. How can I do this in Objective C -- that is, get the 89PNG... string? I tried reading in the image using:
NSData *data = [NSData dataWithContentsOfFile:[[NSBundle mainBundle] pathForResource:@"filename" ofType:@"png"]];
Then I converted to a hex string using:
NSString *dataString = [data description];
dataString = [[dataString stringByTrimmingCharactersInSet:[NSCharacterSet characterSetWithCharactersInString:@"<>"]] stringByReplacingOccurrencesOfString:@" " withString:@""];
Which then left me with something that looks close:
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
But unfortunately not close enough. What do I do next to convert this string to the 89PNG... string?
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我根据 Tumblr 发布的 Python 代码弄清楚了如何根据 Tumblr 的多照片上传需求对十六进制数据进行 url 编码，并且我创建了一个类别，它将 NSData 从图像文件转换为 url 编码的十六进制字符串。可能有一种更有效/更快的方法来做到这一点......有人吗？
编辑：我已经创建了一个 GitHub 项目来负责此转换。
I figured out how to url encode the hex data according to Tumblr's multiple photo upload needs based on its posted Python code, and I created a category that will convert NSData from an image file to the url encoded hex string. There's probably a more efficient / faster way to do this... anyone?
Edit: I've created a GitHub project that takes care of this transformation.
您可以使用 NSString stringByAddingPercentEscapesUsingEncoding。不过，我不知道如何获得原始的 \-转义字符串。
（整个事情看起来很奇怪。）
You can do the % encoding by using NSString stringByAddingPercentEscapesUsingEncoding. I don't know how you get the original \-escaped string, though.
(The whole thing seems quite peculiar.)