前言
接到一个提升App里h5的加载速度优化的问题，参考了很多文章后决定从webview缓存池、并行加载开始
1、统计从的耗时
点击入口->controller创建(init)->设置访问的url地址->调用webview的loadRequest->webview回调start->webview回调finish
统计发现，在调用点击入口到loadRequest这个过程耗费了0.5s左右，
1、于是参考VasSonic在Controller初始化Init时就调用初始好Webview，后来改成在APP启动时就创建一个Webview的缓存池，这样在页面一开始时就已经有webkit内核初始化好的Webview
2、在设置好url后立马调用Webview的loadRequest
但是这个过程中遇到了几个问题，在使用Webview缓存池使用Webview时会有Webview留存上次访问栈的问题，同时在下次请求时还会先展示上次请求过的内容，具体解决办法如下：
清空Webview的缓存栈：执行js方法
[webView evaluateJavaScript@" window.location.replace( 'https://www.baidu.com' )"]
删除上次访问的内容
[webView evaluateJavaScript@"window.document.body.remove();"]
清空sessionStorage里的内容
[webView evaluateJavaScript@"window.sessionStorage.removeItem(\"token\");"]
清空locationStorage里的内容
[webView evaluateJavaScript@"window.localStorage.removeItem(\"token\");"]
清空cookie里的内容
[webView evaluateJavaScript:@"document.cookie = \"token=xxx;expires=Thu, 01 Jan 1970 00:00:01 GMT;path=/;\""]
完整处理分类：
WKWebView+Test.h
#import <WebKit/WebKit.h>
NS_ASSUME_NONNULL_BEGIN
@interface WKWebView (Test)
// 删除webview里的内容
- (void)test_clearBody;
/// 替换url请求，清空访问栈
- (void)test_replaceUrl:(NSString *)url;
/// 清除LocalStorage里的内容
- (void)test_deleLocalStorage:(NSString *)key;
/// 清除SessionStorage里的内容
- (void)test_deleSessionStorage:(NSString *)key;
/// 清除cookie里的内容
- (void)test_deleCookie:(NSString *)key path:(NSString *)path;
@end
NS_ASSUME_NONNULL_END
WKWebView+Test.m
#import "WKWebView+Test.h"
@implementation WKWebView (Test)
// 删除webview里的内容
- (void)test_clearBody{
[self evaluateJavaScript@"window.document.body.remove();"]
}
/// 替换url请求，清空访问栈
- (void)test_replaceUrl:(NSString *)url {
if ([url.lowercaseString hasPrefix:@"http"]) {
NSString *href = [NSString stringWithFormat:@"window.location.replace('%@')",url];
[self evaluateJavaScript:href completionHandler:nil];
}
}
/// 清除LocalStorage里的内容
- (void)test_deleLocalStorage:(NSString *)key {
NSString *text = [NSString stringWithFormat:@"window.localStorage.removeItem(\"%@\",\"\");",key];
[self evaluateJavaScript:text completionHandler:nil];
}
/// 清除SessionStorage里的内容
- (void)test_deleSessionStorage:(NSString *)key {
NSString *text = [NSString stringWithFormat:@"window.sessionStorage.removeItem(\"%@\",\"\");",key];
[self evaluateJavaScript:text completionHandler:nil];
}
/// 清除cookie里的内容
- (void)test_deleCookie:(NSString *)key path:(NSString *)path {
NSString *text = [NSString stringWithFormat:@"document.cookie = \"%@=empty;expires=Thu, 01 Jan 1970 00:00:01 GMT;path=%@;\"",key,path];
[self evaluateJavaScript:text completionHandler:nil];
}
@end
针对
WKWebview请求网络时cookie丢失的问题，对重定向的请求都重新将cookie读取出来放入到请求的header的cookie里
- (void)webView:(WKWebView *)webView decidePolicyForNavigationAction:(WKNavigationAction *)navigationAction decisionHandler:(void (^)(WKNavigationActionPolicy))decisionHandler {
[self redirectRequest: navigationAction.request];
decisionHandler(WKNavigationActionPolicyAllow);
}
- (NSURLRequest *)redirectRequest:(NSURLRequest *)request
{
NSMutableURLRequest *redirectRequest;
if ([request isKindOfClass:[NSMutableURLRequest class]]) {
redirectRequest = (NSMutableURLRequest *)request;
} else {
redirectRequest = [request mutableCopy];
}
NSArray<NSHTTPCookie *> *cookies = [NSHTTPCookieStorage sharedHTTPCookieStorage].cookies;
NSDictionary *cookieHeaders = [NSHTTPCookie requestHeaderFieldsWithCookies:cookies];
if (originCookies.count) {
NSMutableDictionary *redirectHeaders = request.allHTTPHeaderFields.mutableCopy;
[redirectHeaders setValuesForKeysWithDictionary:cookieHeaders];
redirectRequest.allHTTPHeaderFields = redirectHeaders;
}
return redirectRequest;
}
延伸阅读：
