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Diffstat (limited to 'app/src/main/java/moe/yuuta/gplicense/ServerManagedPolicy.java')
| -rw-r--r-- | app/src/main/java/moe/yuuta/gplicense/ServerManagedPolicy.java | 284 |
1 files changed, 284 insertions, 0 deletions
diff --git a/app/src/main/java/moe/yuuta/gplicense/ServerManagedPolicy.java b/app/src/main/java/moe/yuuta/gplicense/ServerManagedPolicy.java new file mode 100644 index 0000000..8355cb8 --- /dev/null +++ b/app/src/main/java/moe/yuuta/gplicense/ServerManagedPolicy.java @@ -0,0 +1,284 @@ +package moe.yuuta.gplicense; + +import android.content.Context; +import android.content.SharedPreferences; + +import com.elvishew.xlog.Logger; +import com.elvishew.xlog.XLog; + +import java.net.URI; +import java.net.URISyntaxException; +import java.util.HashMap; +import java.util.Map; + +import moe.yuuta.gplicense.util.URIQueryDecoder; + +/** + * Default policy. All policy decisions are based off of response data received + * from the licensing service. Specifically, the licensing server sends the + * following information: response validity period, error retry period, + * error retry count and a URL for restoring app access in unlicensed cases. + * <p> + * These values will vary based on the the way the application is configured in + * the Google Play publishing console, such as whether the application is + * marked as free or is within its refund period, as well as how often an + * application is checking with the licensing service. + * <p> + * Developers who need more fine grained control over their application's + * licensing policy should implement a custom Policy. + */ +public class ServerManagedPolicy implements Policy { + private final Logger logger = XLog.tag("DefPolicy").build(); + private static final String PREFS_FILE = "DefPol"; + private static final String PREF_LAST_RESPONSE = "la_resp"; + private static final String PREF_VALIDITY_TIMESTAMP = "ts"; + private static final String PREF_RETRY_UNTIL = "ret_utl"; + private static final String PREF_MAX_RETRIES = "max_ret"; + private static final String PREF_RETRY_COUNT = "ret_am"; + private static final String PREF_LICENSING_URL = "l_url"; + private static final String DEFAULT_VALIDITY_TIMESTAMP = "0"; + private static final String DEFAULT_RETRY_UNTIL = "0"; + private static final String DEFAULT_MAX_RETRIES = "0"; + private static final String DEFAULT_RETRY_COUNT = "0"; + + private static final long MILLIS_PER_MINUTE = 60 * 1000; + + private long mValidityTimestamp; + private long mRetryUntil; + private long mMaxRetries; + private long mRetryCount; + private long mLastResponseTime = 0; + private int mLastResponse; + private String mLicensingUrl; + private PreferenceObfuscator mPreferences; + + /** + * @param context The context for the current application + * @param obfuscator An obfuscator to be used with preferences. + */ + public ServerManagedPolicy(Context context, Obfuscator obfuscator) { + // Import old values + SharedPreferences sp = context.getSharedPreferences(PREFS_FILE, Context.MODE_PRIVATE); + mPreferences = new PreferenceObfuscator(sp, obfuscator); + mLastResponse = Integer.parseInt( + mPreferences.getString(PREF_LAST_RESPONSE, Integer.toString(Policy.RETRY))); + mValidityTimestamp = Long.parseLong(mPreferences.getString(PREF_VALIDITY_TIMESTAMP, + DEFAULT_VALIDITY_TIMESTAMP)); + mRetryUntil = Long.parseLong(mPreferences.getString(PREF_RETRY_UNTIL, DEFAULT_RETRY_UNTIL)); + mMaxRetries = Long.parseLong(mPreferences.getString(PREF_MAX_RETRIES, DEFAULT_MAX_RETRIES)); + mRetryCount = Long.parseLong(mPreferences.getString(PREF_RETRY_COUNT, DEFAULT_RETRY_COUNT)); + mLicensingUrl = mPreferences.getString(PREF_LICENSING_URL, null); + } + + /** + * Process a new response from the license server. + * <p> + * This data will be used for computing future policy decisions. The + * following parameters are processed: + * <ul> + * <li>VT: the timestamp that the client should consider the response valid + * until + * <li>GT: the timestamp that the client should ignore retry errors until + * <li>GR: the number of retry errors that the client should ignore + * <li>LU: a deep link URL that can enable access for unlicensed apps (e.g. + * buy app on the Play Store) + * </ul> + * + * @param response the result from validating the server response + * @param rawData the raw server response data + */ + public void processServerResponse(int response, ResponseData rawData) { + + // Update retry counter + if (response != Policy.RETRY) { + setRetryCount(0); + } else { + setRetryCount(mRetryCount + 1); + } + + // Update server policy data + Map<String, String> extras = decodeExtras(rawData); + if (response == Policy.LICENSED) { + mLastResponse = response; + // Reset the licensing URL since it is only applicable for NOT_LICENSED responses. + setLicensingUrl(null); + setValidityTimestamp(extras.get("VT")); + setRetryUntil(extras.get("GT")); + setMaxRetries(extras.get("GR")); + } else if (response == Policy.NOT_LICENSED) { + // Clear out stale retry params + setValidityTimestamp(DEFAULT_VALIDITY_TIMESTAMP); + setRetryUntil(DEFAULT_RETRY_UNTIL); + setMaxRetries(DEFAULT_MAX_RETRIES); + // Update the licensing URL + setLicensingUrl(extras.get("LU")); + } + + setLastResponse(response); + mPreferences.commit(); + } + + /** + * Set the last license response received from the server and add to + * preferences. You must manually call PreferenceObfuscator.commit() to + * commit these changes to disk. + * + * @param l the response + */ + private void setLastResponse(int l) { + mLastResponseTime = System.currentTimeMillis(); + mLastResponse = l; + mPreferences.putString(PREF_LAST_RESPONSE, Integer.toString(l)); + } + + /** + * Set the current retry count and add to preferences. You must manually + * call PreferenceObfuscator.commit() to commit these changes to disk. + * + * @param c the new retry count + */ + private void setRetryCount(long c) { + mRetryCount = c; + mPreferences.putString(PREF_RETRY_COUNT, Long.toString(c)); + } + + public long getRetryCount() { + return mRetryCount; + } + + /** + * Set the last validity timestamp (VT) received from the server and add to + * preferences. You must manually call PreferenceObfuscator.commit() to + * commit these changes to disk. + * + * @param validityTimestamp the VT string received + */ + private void setValidityTimestamp(String validityTimestamp) { + Long lValidityTimestamp; + try { + lValidityTimestamp = Long.parseLong(validityTimestamp); + } catch (NumberFormatException e) { + // No response or not parsable, expire in one minute. + logger.w("License validity timestamp (VT) missing, caching for a minute"); + lValidityTimestamp = System.currentTimeMillis() + MILLIS_PER_MINUTE; + validityTimestamp = Long.toString(lValidityTimestamp); + } + + mValidityTimestamp = lValidityTimestamp; + mPreferences.putString(PREF_VALIDITY_TIMESTAMP, validityTimestamp); + } + + public long getValidityTimestamp() { + return mValidityTimestamp; + } + + /** + * Set the retry until timestamp (GT) received from the server and add to + * preferences. You must manually call PreferenceObfuscator.commit() to + * commit these changes to disk. + * + * @param retryUntil the GT string received + */ + private void setRetryUntil(String retryUntil) { + Long lRetryUntil; + try { + lRetryUntil = Long.parseLong(retryUntil); + } catch (NumberFormatException e) { + // No response or not parsable, expire immediately + logger.w("License retry timestamp (GT) missing, grace period disabled"); + retryUntil = "0"; + lRetryUntil = 0l; + } + + mRetryUntil = lRetryUntil; + mPreferences.putString(PREF_RETRY_UNTIL, retryUntil); + } + + public long getRetryUntil() { + return mRetryUntil; + } + + /** + * Set the max retries value (GR) as received from the server and add to + * preferences. You must manually call PreferenceObfuscator.commit() to + * commit these changes to disk. + * + * @param maxRetries the GR string received + */ + private void setMaxRetries(String maxRetries) { + Long lMaxRetries; + try { + lMaxRetries = Long.parseLong(maxRetries); + } catch (NumberFormatException e) { + // No response or not parsable, expire immediately + logger.w("Licence retry count (GR) missing, grace period disabled"); + maxRetries = "0"; + lMaxRetries = 0l; + } + + mMaxRetries = lMaxRetries; + mPreferences.putString(PREF_MAX_RETRIES, maxRetries); + } + + public long getMaxRetries() { + return mMaxRetries; + } + + /** + * Set the license URL value (LU) as received from the server and add to preferences. You must + * manually call PreferenceObfuscator.commit() to commit these changes to disk. + * + * @param url the LU string received + */ + private void setLicensingUrl(String url) { + mLicensingUrl = url; + mPreferences.putString(PREF_LICENSING_URL, url); + } + + public String getLicensingUrl() { + return mLicensingUrl; + } + + /** + * {@inheritDoc} + * + * This implementation allows access if either:<br> + * <ol> + * <li>a LICENSED response was received within the validity period + * <li>a RETRY response was received in the last minute, and we are under + * the RETRY count or in the RETRY period. + * </ol> + */ + public boolean allowAccess() { + long ts = System.currentTimeMillis(); + if (mLastResponse == Policy.LICENSED) { + // Check if the LICENSED response occurred within the validity timeout. + if (ts <= mValidityTimestamp) { + // Cached LICENSED response is still valid. + return true; + } + } else if (mLastResponse == Policy.RETRY && + ts < mLastResponseTime + MILLIS_PER_MINUTE) { + // Only allow access if we are within the retry period or we haven't used up our + // max retries. + return (ts <= mRetryUntil || mRetryCount <= mMaxRetries); + } + return false; + } + + private Map<String, String> decodeExtras(ResponseData rawData) { + Map<String, String> results = new HashMap<String, String>(); + if (rawData == null) { + return results; + } + + try { + URI rawExtras = new URI("?" + rawData.extra); + URIQueryDecoder.DecodeQuery(rawExtras, results); + } catch (URISyntaxException e) { + logger.w("Invalid syntax error while decoding extras data from server."); + } + return results; + } + +}
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