iOS WebView使用Ajax與iOS的交互
iOS 使用Ajax實現與Javascript同步異步交互javascript
實現原理：java
1.Ajax能夠實現同步與異步請求 2.UIWebView能夠實現Ajax跨域請求 3.NSURLProtocol能夠攔截Ajax請求 4.NSURLProtocol能夠實現模擬響應結果
須要解決的問題：ajax
1.實現NSURLProtocol攔截Ajax請求 2.實現Ajax跨域，解決Ajax預檢請求問題 3.實現NSURLProtocol返回響應
對於上述問題，咱們定義本身的NSURLProtocol跨域
#import <Foundation/Foundation.h> @interface MyURLProtocol : NSURLProtocol @end
代碼實現app
咱們這裏指定schema爲 oschina://dom
對於其中可能遇到預檢請求問題，請參閱（Ajax跨域(CROS)請求中的Preflighted Requests）異步
@interface MyURLProtocol()
@property(nomatic,strong) NSMutableDictionary * reponseHeader;
@end
@implementation MyURLProtocol
//複寫canInitWithRequest，決定是否攔截請求
+(BOOL)canInitWithRequest:(NSURLRequest *)request{
//這裏實現對 oschina://syncHttpRequest和oschina://asyncHttpRequest攔截
if(request.URL.scheme!=nil && [[request.URL.scheme lowercaseString] isEqualToString:@"oschina"])
{
if([request.URL.host isEqualToString:@"syncHttpRequest"] || [request.URL.host isEqualToString:@"asyncHttpRequest"])
{
if(_reponseHeader==nil)
{
_reponseHeader = @{
@"Access-Control-Allow-Credentials":@"true",
@"Access-Control-Allow-Origin":@"*",
@"Access-Control-Expose-Headers":@"jsStr",
@"Access-Control-Allow-Methods":@"GET,POST,PUT,OPTIONS,HEAD",
@"Access-Control-Allow-Headers":@"Origin,jsStr,Content-Type,X-Request-Width",
@"Access-Control-Max-Age":@"10",
@"Cache-Control":@"no-cache,private",
@"Pragma":@"no-cache,no-store",
@"Expires":@"0",
@"Connection":@"Close"
};
}
return YES;
}
}
//若是不攔截，則返回NO
return NO;
}
//複寫 canonicalRequestForRequest ,加工請求，這裏咱們能夠不加工，直接使用req
+ (NSURLRequest*) canonicalRequestForRequest:(NSURLRequest *)req
{
return req;
}
//複寫startLoading,並處理預檢請求
- (void) startLoading{
//處理跨域操做,若是是options操做。若是是跨域訪問會發送一個options請求，須要response一個權限纔會繼續走head請求
//此外，ajax發送的數據沒法被接收，須要一個自定義請求頭X-Javascript-Header，用來javascript->iOS傳遞數據
if ([self.request.HTTPMethod isEqualToString:@"OPTIONS"])
{
NSDictionary * fields_resp = _reponseHeader;
//響應ajax預檢請求
NSHTTPURLResponse *response = [[NSHTTPURLResponse alloc] initWithURL:[self.request URL] statusCode:200 HTTPVersion:@"1.1" headerFields:fields_resp];
[[self client] URLProtocol: self didReceiveResponse:response cacheStoragePolicy:NSURLCacheStorageNotAllowed];
[[self client] URLProtocol:self didLoadData:[NSData data]];
[[self client] URLProtocolDidFinishLoading:self];
}else{
//實現對ajax正式請求的解析與響應
[self doRequestToResponse];
}
}
-(void) doRequestToResponse
{
NSDictionary *dic = [self.request.allHTTPHeaderFields copy];
NSString *jsStr = dic[@"X-Javascript-Header"]; //獲取響應頭數據
NSString * userAgentInStorage = [[NSUserDefaults standardUserDefaults] stringForKey:@"UserAgent"];
NSString * userAgent = dic[@"User-Agent"];
//必要時保存user-Agent
if([NSString isEmptyOrNil:userAgentInStorage] && ![NSString isEmptyOrNil:userAgent])
{
[[NSUserDefaults standardUserDefaults] setObject:userAgent forKey:@"UserAgent"];
[[NSUserDefaults standardUserDefaults] synchronize];
}
if([NSString isEmptyOrNil:jsStr])
{
[self sendRequestErrorToClient];
return;
}
if([jsStr hasPrefix:@"@"])
{
jsStr = [jsStr stringByReplacingOccurrencesOfString:@"@" withString:@""];
}
NSData *data = [GTMBase64 decodeString:jsStr];
jsStr = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
// 轉換
jsStr = [jsStr stringByReplacingOccurrencesOfString:@"\n" withString:@"\\n"];
jsStr = [jsStr stringByReplacingOccurrencesOfString:@"\r" withString:@"\\r"];
jsStr = [jsStr stringByReplacingOccurrencesOfString:@"\t" withString:@"\\t"];
jsStr = [jsStr stringByReplacingOccurrencesOfString:@"\0" withString:@"\\0"];
NSMutableDictionary *jsDic = [jsStr mutableObjectFromJSONString];
if(jsDic==nil)
{
NSString * tempJsStr = [jsStr stringByReplacingOccurrencesOfString:@"\\" withString:@"\\\\"];
jsDic = [tempJsStr mutableObjectFromJSONString];
}
if(jsDic==nil)
{
[UMJS showToast:@"參數解析失敗！"];
return;
}
NSString *serviceName= jsDic[@"service"];
NSString *methodName = jsDic[@"method"];
id params = jsDic["params"];
[------------------處理響應的請結果------------------------]
//1.開始處理，略
//發送相應數據到Ajax端,假定結果爲result
NSString * response = [@{@"result":result,@"msg":@"Hello World",@"code":@1} JSONString];
[self sendResponseToClient:response];
[------------------處理響應的請結果------------------------]
}
-(void) sendResponseToClient:(NSString *) str
{
NSData *repData = [str dataUsingEncoding:NSUTF8StringEncoding];
NSMutableDictionary *respHeader = [NSMutableDictionary dictionaryWithDictionary:fields_resp];
respHeader[@"Content-Length"] = [NSString stringWithFormat:@"%ld",repData.length];
NSHTTPURLResponse *response = [[NSHTTPURLResponse alloc] initWithURL:[self.request URL] statusCode:200 HTTPVersion:@"1.1" headerFields:respHeader];
[[self client] URLProtocol: self didReceiveResponse:response cacheStoragePolicy:NSURLCacheStorageNotAllowed];
[[self client] URLProtocol:self didLoadData:repData];
[[self client] URLProtocolDidFinishLoading:self];
}
//發送錯誤請求信息
-(void) sendRequestErrorToClient
{
NSData *data = [@"" dataUsingEncoding:NSUTF8StringEncoding];
NSDictionary * fields_resp =_reponseHeader;
NSHTTPURLResponse *response = [[NSHTTPURLResponse alloc] initWithURL:[self.request URL] statusCode:400 HTTPVersion:@"1.1" headerFields:fields_resp];
[[self client] URLProtocol: self didReceiveResponse:response cacheStoragePolicy:NSURLCacheStorageNotAllowed];
[[self client] URLProtocol:self didLoadData:data];
[[self client] URLProtocolDidFinishLoading:self];
}
- (void) stopLoading{
// NSLog(@"stopLoading");
}
//處理跳轉
(NSURLRequest *)connection:(NSURLConnection *)connection willSendRequest:(NSURLRequest *)request redirectResponse:(NSURLResponse *)response {
if ([response isKindOfClass:[NSHTTPURLResponse class]])
{
NSHTTPURLResponse *HTTPResponse = (NSHTTPURLResponse *)response;
if ([HTTPResponse statusCode] == 301 || [HTTPResponse statusCode] == 302)
{
NSMutableURLRequest *mutableRequest = [request mutableCopy];
[mutableRequest setURL:[NSURL URLWithString:[[HTTPResponse allHeaderFields] objectForKey:@」Location」]]];
request = [mutableRequest copy];
[[self client] URLProtocol:self wasRedirectedToRequest:request redirectResponse:response];
}
}
return request;
}
自定義結束以後，咱們須要在AppDetegate或者UIViewController註冊一下才行，注意：屢次註冊也是能夠的，不會形成屢次攔截。async
[NSURLProtocol registerClass:[UyURLProtocol class]];
經過這種方式，咱們能夠實現iOS端數據處理，在Javascript端咱們須要實現2類調用，同步和異步this
//異步請求
function sendAsyncAjax(xJavascript, onload, onerror) {
var xhr, results, url;
url = 'oschina://asyncHttpRequest?rnd='+Math.random();
xhr = new XMLHttpRequest();
try{
xhr.open('POST', url, true);
xhr.setRequestHeader("Content-Type", "application/x-www-form-urlencoded");
xhr.setRequestHeader("Cache-Control", "no-cache,private");
xhr.setRequestHeader("Pragma", "no-cache,no-store");
xhr.setRequestHeader("User-Agent", navigator.userAgent);
//經過X-Javascript-Header發送數據到iOS,注意，使用第三方Base64 encode
xhr.setRequestHeader("X-Javascript-Header", Base64Util.encode(xJavascript));
xhr.onload = function (e) {
if (this.status === 200) {
results = JSON.parse(xhr.responseText);
onload(results);
}else{
onload({'e':e});
}
};
xhr.onerror = function (e) {
onerror({'e':e});
};
}catch(exception){
console.error(exception);
}finally{
try{
xhr.send(null);
}catch(exception2){}
}
}
//同步請求
function sendSyncAjax(xJavascript) {
var xhr, results, url;
url = 'oschina://syncHttpRequest?rnd='+Math.random();
xhr = new XMLHttpRequest();
try{
xhr.open('POST', url, true);
xhr.setRequestHeader("Content-Type", "application/x-www-form-urlencoded");
xhr.setRequestHeader("Cache-Control", "no-cache,private");
xhr.setRequestHeader("Pragma", "no-cache,no-store");
xhr.setRequestHeader("User-Agent", navigator.userAgent);
//經過X-Javascript-Header發送數據到iOS,注意，使用第三方Base64 encode
xhr.setRequestHeader("X-Javascript-Header", Base64Util.encode(xJavascript));
}catch(exception){
console.error(exception);
}finally{
try{
xhr.send(null);
}catch(exception2){}
}
if (xhr.readyState == 4) {
if (xhr.status == 200) {
return xhr.execXhr.responseText;
} else {
return xhr.execXhr.responseText;
}
}
return {};
}
而後咱們經過javascript調用url
var script = JSON.stringify({service:"NetworkUtil",method:"getNetworkInfo",params:{}};
sendAsyncAjax(script ,function(result){
}, function(error){
});
或者
var script = JSON.stringify({service:"NetworkUtil",method:"getNetworkInfo",params:{}};
var result = sendSyncAjax(script);
通常來講NetworkUtil能夠調用的方法必須是類方法
@implementation NetworkUtil
+(NSString * )getNetworkInfo
{
NSString * result = [略];
return result;
}
@end
咱們這裏實現了iOS平臺上同步異步的方法，Android平臺有系統提供的javascriptInterface接口，固然，咱們想要實現和本篇iOS相似的方式，咱們可使用ServerSocket方式來實現，具體過程可能使用到信號量的概念，這裏再也不贅述，又須要能夠留言。
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