| /* |
| * Copyright 2022 Google LLC |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| package com.google.android.libraries.mobiledatadownload.file.backends; |
| |
| import android.content.Context; |
| import android.net.Uri; |
| import android.text.TextUtils; |
| import com.google.android.libraries.mobiledatadownload.file.common.MalformedUriException; |
| import com.google.common.base.Splitter; |
| import com.google.common.io.BaseEncoding; |
| import java.util.List; |
| |
| /** Helper class for "blobstore" URIs. */ |
| public final class BlobUri { |
| // Uri path constants |
| public static final String SCHEME = "blobstore"; |
| private static final String LEASE_URI_SUFFIX = ".lease"; |
| private static final String CHECKSUM_SEPARATOR = "."; |
| private static final String ALL_LEASES_PATH = "*" + LEASE_URI_SUFFIX; |
| private static final int PATH_SIZE = 1; |
| // Uri query constants |
| private static final int QUERY_PARAMETERS = 1; // A single query element called expiryDateSecs |
| private static final String EXPIRY_DATE_QUERY_KEY = "expiryDateSecs"; |
| // MalformedException message strings |
| private static final String EXPECTED_BLOB_URI_PATH = "<non_empty_checksum>"; |
| private static final String EXPECTED_LEASE_URI_PATH = "<non_empty_checksum>.lease"; |
| private static final String EXPECTED_LEASE_URI_QUERY = "expiryDateSecs=<expiryDateSecs>"; |
| |
| private static final Splitter SPLITTER = Splitter.on(CHECKSUM_SEPARATOR); |
| |
| /** Returns a "blobstore" scheme URI. */ |
| public static Builder builder(Context context) { |
| return new Builder(context); |
| } |
| |
| private BlobUri() {} |
| |
| static void validateUri(Uri uri) throws MalformedUriException { |
| validatePath(uri); |
| validateQuery(uri); |
| } |
| |
| /** |
| * Validates the path of the "blobstore" scheme URI. |
| * |
| * <p>Theare only two permitted paths: |
| * |
| * <ul> |
| * <li><non_empty_checksum> |
| * <li><non_empty_checksum>.lease |
| * </ul> |
| */ |
| private static void validatePath(Uri uri) throws MalformedUriException { |
| List<String> pathSegments = uri.getPathSegments(); |
| if (pathSegments.size() != PATH_SIZE || !hasValidChecksumExtension(pathSegments.get(0))) { |
| throw new MalformedUriException( |
| String.format( |
| "The uri is malformed, expected %s or %s but found %s", |
| EXPECTED_BLOB_URI_PATH, EXPECTED_LEASE_URI_PATH, uri.getPath())); |
| } |
| } |
| |
| private static boolean hasValidChecksumExtension(String path) { |
| return SPLITTER.splitToList(path).size() == 1 |
| || (isLeaseUri(path) && !TextUtils.equals(path, LEASE_URI_SUFFIX)); |
| } |
| |
| /** Returns true if the path is of type "<checksum>.lease". */ |
| static boolean isLeaseUri(String path) { |
| return path.endsWith(LEASE_URI_SUFFIX); |
| } |
| |
| /** Returns true if the path matches "*.lease". */ |
| static boolean isAllLeasesUri(String path) { |
| if (path.startsWith("/")) { |
| path = path.substring(1); |
| } |
| return TextUtils.equals(path, ALL_LEASES_PATH); |
| } |
| |
| /** |
| * If available, validates the query part of the "blobstore" scheme URI. |
| * |
| * <p>There is one permitted query parameter: expiryDateSecs=<expiryDateSecs>. |
| */ |
| private static void validateQuery(Uri uri) throws MalformedUriException { |
| if (TextUtils.isEmpty(uri.getQuery())) { |
| return; |
| } |
| if (uri.getQueryParameterNames().size() != QUERY_PARAMETERS |
| || uri.getQueryParameter(EXPIRY_DATE_QUERY_KEY) == null) { |
| throw new MalformedUriException( |
| String.format( |
| "The uri query is malformed, expected %s but found query %s", |
| EXPECTED_LEASE_URI_QUERY, uri.getQuery())); |
| } |
| } |
| |
| /** |
| * Returns the checksum bytes encoded in the {@code path}. |
| * |
| * <p>To decode the bytes from the path, it uses the same encoding used by {@code // |
| * com.google.android.libraries.mobiledatadownload.internal.downloader.FileValidator}. |
| */ |
| static byte[] getChecksum(String path) { |
| if (path.startsWith("/")) { |
| path = path.substring(1); |
| } |
| return BaseEncoding.base16().lowerCase().decode(SPLITTER.splitToList(path).get(0)); |
| } |
| |
| /* Parses the {@code query} and returns the encoded {@code expiryDateSecs}. */ |
| static long getExpiryDateSecs(Uri uri) throws MalformedUriException { |
| String query = uri.getQuery(); |
| if (TextUtils.isEmpty(query)) { |
| throw new MalformedUriException( |
| String.format("The uri query is null or empty, expected %s", EXPECTED_LEASE_URI_QUERY)); |
| } |
| String expiryDateSecsString = uri.getQueryParameter(EXPIRY_DATE_QUERY_KEY); |
| if (expiryDateSecsString == null) { |
| throw new MalformedUriException( |
| String.format( |
| "The uri query is malformed, expected %s but found %s", |
| EXPECTED_LEASE_URI_QUERY, query)); |
| } |
| long expiryDateSecs = Long.parseLong(expiryDateSecsString); |
| return expiryDateSecs; |
| } |
| |
| /** A builder for "blobstore" scheme Uris. */ |
| public static class Builder { |
| private String path = ""; |
| private String packageName = ""; |
| private long expiryDateSecs; |
| |
| private Builder(Context context) { |
| // TODO(b/149260496): remove/change meaning to packageName |
| this.packageName = context.getPackageName(); |
| } |
| |
| public Builder setBlobParameters(String checksum) { |
| path = checksum; |
| return this; |
| } |
| |
| public Builder setLeaseParameters(String checksum, long expiryDateSecs) { |
| path = checksum + LEASE_URI_SUFFIX; |
| this.expiryDateSecs = expiryDateSecs; |
| return this; |
| } |
| |
| public Builder setAllLeasesParameters() { |
| path = ALL_LEASES_PATH; |
| return this; |
| } |
| |
| public Uri build() throws MalformedUriException { |
| Uri.Builder uriBuilder = new Uri.Builder().scheme(SCHEME).authority(packageName).path(path); |
| if (isLeaseUri(path) && !isAllLeasesUri(path)) { |
| uriBuilder.appendQueryParameter(EXPIRY_DATE_QUERY_KEY, String.valueOf(expiryDateSecs)); |
| } |
| Uri uri = uriBuilder.build(); |
| validateUri(uri); |
| return uri; |
| } |
| } |
| } |