地理地图,天堂的证明,乔·阿布索隆
一、具体问题
开发的过程中，发现某个界面部分图片的显示出现了问题只显示占位图片，取出图片的url在浏览器却是能打开的，各种尝试甚至找同行的朋友帮忙在他们项目里展示都会存在问题，最终发现通过第三方框架sdwebimage或者yywebimage下载带有逗号的url图片链接都会下载失败，在下载方法完成的回调block里面打印信息如下：
error domain=nsurlerrordomain code=403 "(null)"
现列举两个不能正常展示的图片url：
http://img1.imgtn.bdimg.com/it/u=3044191397,2911599132&fm=27&gp=0.jpg http://img2.imgtn.bdimg.com/it/u=3509004173,840437551&fm=27&gp=0.jpg
有兴趣的小伙伴可以拿到自己的项目里试试
二、问题原因
网上有小伙伴提出是因为缺少user-agent用户代理导致的。只有设置了用户代理，才能访问到这张带有逗号的url图片。至于这个用户代理的格式，只要有值或者约定的特定格式字符串都可以。
三、具体解决
1.第三方框架yywebimage
找到yywebimagemanager.m文件，定位到设置http请求头的属性即_headers的地方，加入一个user-agent的键值对，具体改动可以看下面的方法
我要评论- (instancetype)initwithcache:(yyimagecache *)cache queue:(nsoperationqueue *)queue{
self = [super init];
if (!self) return nil;
_cache = cache;
_queue = queue;
_timeout = 15.0;
nsstring *useragent = @"";
useragent = [nsstring stringwithformat:@"%@/%@ (%@; ios %@; scale/%0.2f)", [[[nsbundle mainbundle] infodictionary] objectforkey:(__bridge nsstring *)kcfbundleexecutablekey] ?: [[[nsbundle mainbundle] infodictionary] objectforkey:(__bridge nsstring *)kcfbundleidentifierkey], [[[nsbundle mainbundle] infodictionary] objectforkey:@"cfbundleshortversionstring"] ?: [[[nsbundle mainbundle] infodictionary] objectforkey:(__bridge nsstring *)kcfbundleversionkey], [[uidevice currentdevice] model], [[uidevice currentdevice] systemversion], [[uiscreen mainscreen] scale]];
if (useragent) {
if (![useragent canbeconvertedtoencoding:nsasciistringencoding]) {
nsmutablestring *mutableuseragent = [useragent mutablecopy];
if (cfstringtransform((__bridge cfmutablestringref)(mutableuseragent), null, (__bridge cfstringref)@"any-latin; latin-ascii; [:^ascii:] remove", false)) {
useragent = mutableuseragent;
}
}
}
//带有逗号的图片url不显示的问题，重要的是设置代理才能解决
if (yyimagewebpavailable()) {
_headers = @{ @"accept" : @"image/webp,image/*;q=0.8", @"user-agent" : useragent};
} else {
_headers = @{ @"accept" : @"image/*;q=0.8", @"user-agent" : useragent};
}
return self;
}
2.第三方框架sdwebimage
找到sdwebimagedownloader.m文件，也是定位到设置http请求头的属性即_httpheaders的地方，加入一个user-agent的键值对，具体改动可以看下面的方法
- (id)init {
if ((self = [super init])) {
_operationclass = [sdwebimagedownloaderoperation class];
_shoulddecompressimages = yes;
_executionorder = sdwebimagedownloaderfifoexecutionorder;
_downloadqueue = [nsoperationqueue new];
_downloadqueue.maxconcurrentoperationcount = 6;
_urlcallbacks = [nsmutabledictionary new];
/***********************/
nsstring *useragent = @"";
useragent = [nsstring stringwithformat:@"%@/%@ (%@; ios %@; scale/%0.2f)", [[[nsbundle mainbundle] infodictionary] objectforkey:(__bridge nsstring *)kcfbundleexecutablekey] ?: [[[nsbundle mainbundle] infodictionary] objectforkey:(__bridge nsstring *)kcfbundleidentifierkey], [[[nsbundle mainbundle] infodictionary] objectforkey:@"cfbundleshortversionstring"] ?: [[[nsbundle mainbundle] infodictionary] objectforkey:(__bridge nsstring *)kcfbundleversionkey], [[uidevice currentdevice] model], [[uidevice currentdevice] systemversion], [[uiscreen mainscreen] scale]];
if (useragent) {
if (![useragent canbeconvertedtoencoding:nsasciistringencoding]) {
nsmutablestring *mutableuseragent = [useragent mutablecopy];
if (cfstringtransform((__bridge cfmutablestringref)(mutableuseragent), null, (__bridge cfstringref)@"any-latin; latin-ascii; [:^ascii:] remove", false)) {
useragent = mutableuseragent;
}
}
}
/***********************/
#ifdef sd_webp
_httpheaders = [@{@"accept": @"image/webp,image/*;q=0.8", useragent : @"user-agent"} mutablecopy];
#else
_httpheaders = [@{@"accept": @"image/*;q=0.8", useragent : @"user-agent"} mutablecopy];
#endif
_barrierqueue = dispatch_queue_create("com.hackemist.sdwebimagedownloaderbarrierqueue", dispatch_queue_concurrent);
_downloadtimeout = 15.0;
}
return self;
}
或者是直接在uiimageview+webcache.m文件中，在统一下载图片入口最前面添加如下代码
- (void)sd_setimagewithurl:(nsurl *)url placeholderimage:(uiimage *)placeholder options:(sdwebimageoptions)options progress:(sdwebimagedownloaderprogressblock)progressblock completed:(sdwebimagecompletionblock)completedblock {
/***********************/
nsstring *useragent = @"";
useragent = [nsstring stringwithformat:@"%@/%@ (%@; ios %@; scale/%0.2f)", [[[nsbundle mainbundle] infodictionary] objectforkey:(__bridge nsstring *)kcfbundleexecutablekey] ?: [[[nsbundle mainbundle] infodictionary] objectforkey:(__bridge nsstring *)kcfbundleidentifierkey], [[[nsbundle mainbundle] infodictionary] objectforkey:@"cfbundleshortversionstring"] ?: [[[nsbundle mainbundle] infodictionary] objectforkey:(__bridge nsstring *)kcfbundleversionkey], [[uidevice currentdevice] model], [[uidevice currentdevice] systemversion], [[uiscreen mainscreen] scale]];
if (useragent) {
if (![useragent canbeconvertedtoencoding:nsasciistringencoding]) {
nsmutablestring *mutableuseragent = [useragent mutablecopy];
if (cfstringtransform((__bridge cfmutablestringref)(mutableuseragent), null, (__bridge cfstringref)@"any-latin; latin-ascii; [:^ascii:] remove", false)) {
useragent = mutableuseragent;
}
}
[[sdwebimagedownloader shareddownloader] setvalue:useragent forhttpheaderfield:@"user-agent"];
}
/***********************/
[self sd_cancelcurrentimageload];
........省略原源码
}
3.其他第三方下载图片的框架
直接全局搜索字符串"accept"，因为虽然缺少设置user-agent用户代理，但是http请求头一般都会有设置"accept"，所以定位后，直接再加一个user-agent的键值对就可以了
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