public static Cache.Entry parseIgnoreCacheHeaders(
NetworkResponse response, String url, long softttl, long hardttl) {
long now = System.currentTimeMillis();
Map<String, String> headers = response.headers;
long serverDate = 0;
String serverEtag = null;
String headerValue;
headerValue = headers.get("Date");
if (headerValue != null) {
serverDate = parseDateAsEpoch(headerValue);
}
serverEtag = headers.get("ETag");
// entry expires
// completely
final long softExpire = now + softttl;
final long ttl = now + hardttl;
Cache.Entry entry = new Cache.Entry();
entry.data = response.data;
entry.etag = serverEtag;
entry.softTtl = softExpire;
entry.ttl = ttl;
entry.serverDate = serverDate;
entry.responseHeaders = headers;
return entry;
}
/**
* Extracts a {@link Cache.Entry} from a {@link com.android.volley.NetworkResponse}. Cache-control
* headers are ignored. SoftTtl == 3 mins, ttl == 24 hours.
*
* @param response The network response to parse headers from
* @return a cache entry for the given response, or null if the response is not cacheable.
*/
public static Cache.Entry parseIgnoreCacheHeaders(NetworkResponse response) {
long now = System.currentTimeMillis();
Map<String, String> headers = response.headers;
long serverDate = 0;
String serverEtag = null;
String headerValue;
headerValue = headers.get("Date");
if (headerValue != null) {
serverDate = com.android.volley.toolbox.HttpHeaderParser.parseDateAsEpoch(headerValue);
}
serverEtag = headers.get("ETag");
final long cacheHitButRefreshed =
3 * 60 * 1000; // in 3 minutes cache will be hit, but also refreshed on background
final long cacheExpired =
24 * 60 * 60 * 1000; // in 24 hours this cache entry expires completely
final long softExpire = now + cacheHitButRefreshed;
final long ttl = now + cacheExpired;
Cache.Entry entry = new Cache.Entry();
entry.data = response.data;
entry.etag = serverEtag;
entry.softTtl = softExpire;
entry.ttl = ttl;
entry.serverDate = serverDate;
entry.responseHeaders = headers;
return entry;
}
/**
* Extracts a {@link com.android.volley.Cache.Entry} from a {@link
* com.android.volley.NetworkResponse}.
*
* @param response The network response to parse headers from
* @param cacheTime 缓存时间，如果设置了这个值，不管服务器返回是否可以缓存，都会缓存,一天为1000*60*60*24
* @return a cache entry for the given response, or null if the response is not cacheable.
*/
public static Cache.Entry parseCacheHeaders(NetworkResponse response, long cacheTime) {
long now = System.currentTimeMillis();
long softExpire = now + cacheTime;
Cache.Entry entry = parseCacheHeaders(response);
if (null == entry && response.data.length > 0) {
entry = new Cache.Entry();
entry.data = response.data;
entry.serverDate = now;
// Time to Leave 客户端可以通过这个数据来判断当前内容是否过期。
entry.ttl = softExpire;
// 在这个时间内，是否需要刷新
entry.softTtl = softExpire;
}
return entry;
}
/**
* Extracts a {@link Cache.Entry} from a {@link NetworkResponse}.
*
* @param response The network response to parse headers from
* @return a cache entry for the given response, or null if the response is not cacheable.
*/
public static Cache.Entry parseCacheHeaders(NetworkResponse response) {
long now = System.currentTimeMillis();
Map<String, String> headers = response.headers;
long serverDate = 0;
long serverExpires = 0;
long softExpire = 0;
long maxAge = 0;
long lastModify = 0;
boolean hasCacheControl = false;
String serverEtag = null;
String headerValue;
headerValue = headers.get("Date");
if (headerValue != null) {
serverDate = parseDateAsEpoch(headerValue);
}
headerValue = headers.get("Cache-Control");
if (headerValue != null) {
hasCacheControl = true;
String[] tokens = headerValue.split(",");
for (int i = 0; i < tokens.length; i++) {
String token = tokens[i].trim();
if (token.equals("no-cache") || token.equals("no-store")) {
return null;
} else if (token.startsWith("max-age=")) {
try {
maxAge = Long.parseLong(token.substring(8));
} catch (Exception e) {
}
} else if (token.equals("must-revalidate") || token.equals("proxy-revalidate")) {
maxAge = 0;
}
}
}
headerValue = headers.get("Expires");
if (headerValue != null) {
serverExpires = parseDateAsEpoch(headerValue);
}
serverEtag = headers.get("ETag");
// Cache-Control takes precedence over an Expires header, even if both exist and Expires
// is more restrictive.
if (hasCacheControl) {
softExpire = now + maxAge * 1000;
} else if (serverDate > 0 && serverExpires >= serverDate) {
// Default semantic for Expire header in HTTP specification is softExpire.
softExpire = now + (serverExpires - serverDate);
}
headerValue = headers.get("Last-Modified");
if (headerValue != null) {
lastModify = parseDateAsEpoch(headerValue);
}
Cache.Entry entry = new Cache.Entry();
entry.data = response.data;
entry.etag = serverEtag;
entry.softTtl = softExpire;
entry.ttl = entry.softTtl;
entry.serverDate = serverDate;
entry.lastModify = lastModify;
entry.responseHeaders = headers;
return entry;
}