Replace Guava depedency

-- Base64 encoding via Okio
-- MD5 hashing via MessageDigest
-- HmacSHA256 via Mac

All of those algorithms are available at Android API >1

Author: marcinqualaroo

build.gradle

@@ -42,12 +42,10 @@ dependencies {
     compile 'com.squareup.retrofit2:converter-gson:2.3.0' // GSON integration
 
     compile 'com.google.code.gson:gson:2.8.1' // JSON serialization to Java objects
-    compile ('com.google.guava:guava:22.0-android', { // Useful core libraries for Java
-        exclude group: 'com.google.code.findbugs', module: 'jsr305'
-    })
 
     compile 'io.reactivex.rxjava2:rxjava:2.1.2'
     compile "org.jetbrains.kotlin:kotlin-stdlib-jdk8:$kotlin_version" // Observable pattern for async methods
+    compileOnly 'com.google.code.findbugs:jsr305:3.0.2'
 }
 
 javadoc {

src/integTest/java/com/filestack/TestBasicFunctions.java

@@ -1,6 +1,6 @@
 package com.filestack;
 
-import com.google.common.io.Files;
+import okio.Okio;
 import org.junit.AfterClass;
 import org.junit.Assert;
 import org.junit.Rule;
@@ -86,7 +86,7 @@ public void testDownload() throws Exception {
     fileLink.download("/tmp/", downloadFile.getName());
 
     Assert.assertTrue(downloadFile.isFile());
-    byte[] bytes = Files.asByteSource(downloadFile).read();
+    byte[] bytes = Okio.buffer(Okio.source(downloadFile)).readByteArray();
     String content = new String(bytes, "utf-16");
     Assert.assertEquals(uploadUuid, content);
   }

src/integTest/java/com/filestack/TestTransforms.java

@@ -4,13 +4,15 @@
 import com.filestack.transforms.ImageTransform;
 import com.filestack.transforms.tasks.AvTransformOptions;
 import com.filestack.transforms.tasks.CropTask;
-import com.google.common.hash.Hashing;
-import com.google.common.io.Files;
+import okio.ByteString;
+import okio.Okio;
 import org.junit.AfterClass;
 import org.junit.Assert;
 import org.junit.Test;
 
 import java.io.File;
+import java.security.MessageDigest;
+import java.security.NoSuchAlgorithmException;
 import java.util.ArrayList;
 
 public class TestTransforms {
@@ -39,9 +41,10 @@ public void testImageTransform() throws Exception {
     String cropPath = loader.getResource("com/filestack/sample_image_cropped.jpg").getPath();
     File cropFile = new File(cropPath);
 
-    String correct = Files.asByteSource(cropFile).hash(Hashing.sha256()).toString();
-    byte[] bytes = transform.getContent().bytes();
-    String output = Hashing.sha256().hashBytes(bytes).toString();
+    byte[] bytes = Okio.buffer(Okio.source(cropFile)).readByteArray();
+    String correct = ByteString.of(sha256(bytes)).hex();
+    byte[] actualBytes = transform.getContent().bytes();
+    String output = ByteString.of(sha256(actualBytes)).hex();
 
     Assert.assertEquals(correct, output);
   }
@@ -70,9 +73,9 @@ public void testAvTransform() throws Exception {
     String mp3Path = loader.getResource("com/filestack/sample_music.mp3").getPath();
     File mp3File = new File(mp3Path);
 
-    String correct = Files.asByteSource(mp3File).hash(Hashing.sha256()).toString();
+    String correct = ByteString.of(sha256(Okio.buffer(Okio.source(mp3File)).readByteArray())).hex();
     byte[] bytes = mp3FileLink.getContent().bytes();
-    String output = Hashing.sha256().hashBytes(bytes).toString();
+    String output = ByteString.of(bytes).hex();
 
     Assert.assertEquals(correct, output);
   }
@@ -99,4 +102,10 @@ public static void cleanupFiles() {
       }
     }
   }
-}
+
+  private static byte[] sha256(byte[] bytes) throws NoSuchAlgorithmException {
+    MessageDigest md = MessageDigest.getInstance("SHA-256");
+    md.update(bytes);
+    return md.digest();
+  }
+}

src/main/java/com/filestack/Client.java

@@ -6,7 +6,6 @@
 import com.filestack.internal.Util;
 import com.filestack.internal.responses.CloudStoreResponse;
 import com.filestack.transforms.ImageTransform;
-import com.google.common.base.Strings;
 import com.google.gson.Gson;
 import com.google.gson.JsonElement;
 import com.google.gson.JsonObject;
@@ -215,7 +214,7 @@ public Flowable<Progress<FileLink>> uploadAsync(String path, boolean intel, Stor
 
       if (opts == null) {
         opts = new StorageOptions.Builder().filename(inputFile.getName()).build();
-      } else if (Strings.isNullOrEmpty(opts.getFilename())) {
+      } else if (Util.isNullOrEmpty(opts.getFilename())) {
         opts = opts.newBuilder().filename(inputFile.getName()).build();
       }
 

src/main/java/com/filestack/Policy.java

@@ -1,11 +1,10 @@
 package com.filestack;
 
-import com.google.common.base.Charsets;
-import com.google.common.hash.HashFunction;
-import com.google.common.hash.Hashing;
-import com.google.common.io.BaseEncoding;
+import com.filestack.internal.Hash;
+import com.filestack.internal.Util;
 import com.google.gson.Gson;
 
+import java.nio.charset.Charset;
 import java.util.Date;
 
 /**
@@ -150,12 +149,9 @@ public Builder giveFullAccess() {
      */
     public Policy build(String appSecret) {
       Gson gson = new Gson();
-      HashFunction hashFunction = Hashing.hmacSha256(appSecret.getBytes(Charsets.UTF_8));
-
       String jsonPolicy = gson.toJson(this);
-      String encodedPolicy = BaseEncoding.base64Url().encode(jsonPolicy.getBytes(Charsets.UTF_8));
-      String signature = hashFunction.hashString(encodedPolicy, Charsets.UTF_8).toString();
-
+      String encodedPolicy = Util.base64Url(jsonPolicy.getBytes());
+      String signature = Hash.hmacSha256(appSecret.getBytes(Charset.forName("UTF-8")), encodedPolicy.getBytes(Charset.forName("UTF-8")));
       return new Policy(encodedPolicy, signature);
     }
   }

src/main/java/com/filestack/StorageOptions.java

@@ -2,7 +2,6 @@
 
 import com.filestack.internal.Util;
 import com.filestack.transforms.TransformTask;
-import com.google.common.base.Strings;
 import com.google.gson.JsonObject;
 import okhttp3.RequestBody;
 
@@ -64,14 +63,14 @@ public Map<String, RequestBody> getAsPartMap() {
 
     // A name and MIME type must be set for uploads, so we set a default here but not in "build"
     // If we're not using the instance for an upload, we don't want to set these defaults
-    if (Strings.isNullOrEmpty(filename)) {
+    if (Util.isNullOrEmpty(filename)) {
       long timestamp = System.currentTimeMillis() / 1000L;
       filename = String.format(DEFAULT_FILENAME, timestamp);
     }
 
     // There's too many variables in guessing MIME types, esp between platforms
     // Either the user sets it themselves or we use a default
-    if (Strings.isNullOrEmpty(mimeType)) {
+    if (Util.isNullOrEmpty(mimeType)) {
       mimeType = DEFAULT_MIME_TYPE;
     }
 

src/main/java/com/filestack/internal/Hash.java

@@ -0,0 +1,44 @@
+package com.filestack.internal;
+
+import okio.ByteString;
+
+import javax.annotation.Nullable;
+import javax.crypto.Mac;
+import javax.crypto.spec.SecretKeySpec;
+import java.security.InvalidKeyException;
+import java.security.MessageDigest;
+import java.security.NoSuchAlgorithmException;
+
+public final class Hash {
+  private Hash() {}
+
+  @Nullable
+  public static byte[] md5(byte[] bytes) {
+    return md5(bytes, 0, bytes.length);
+  }
+
+  @Nullable
+  public static byte[] md5(byte[] bytes, int offset, int length) {
+    try {
+      MessageDigest md = MessageDigest.getInstance("MD5");
+      md.update(bytes, offset, length);
+      return md.digest();
+    } catch (NoSuchAlgorithmException e) {
+      return null;
+    }
+  }
+
+  @Nullable
+  public static String hmacSha256(byte[] key, byte[] message) {
+    try {
+      Mac mac = Mac.getInstance("HmacSHA256");
+      mac.init(new SecretKeySpec(key, "HmacSHA256"));
+      byte[] hash = mac.doFinal(message);
+      return ByteString.of(hash).hex();
+    } catch (InvalidKeyException e) {
+      return null;
+    } catch (NoSuchAlgorithmException e) {
+      return null;
+    }
+  }
+}

src/main/java/com/filestack/internal/Networking.java

@@ -2,7 +2,6 @@
 
 import java.util.concurrent.TimeUnit;
 
-import com.google.common.graph.Network;
 import okhttp3.OkHttpClient;
 import retrofit2.Retrofit;
 import retrofit2.converter.gson.GsonConverterFactory;

src/main/java/com/filestack/internal/UploadTransferFunc.java

@@ -1,9 +1,6 @@
 package com.filestack.internal;
 
 import com.filestack.internal.responses.UploadResponse;
-import com.google.common.hash.HashCode;
-import com.google.common.hash.Hashing;
-import com.google.common.io.BaseEncoding;
 import io.reactivex.BackpressureStrategy;
 import io.reactivex.Flowable;
 import io.reactivex.FlowableEmitter;
@@ -48,20 +45,14 @@ public void subscribe(FlowableEmitter<Prog> e) throws Exception {
 
   /** Get parameters from Filestack for the upload to S3. */
   private UploadResponse getUploadParams(int size) throws Exception {
-
-    // Deprecated because MD5 is insecure not because this is unmaintained
-    @SuppressWarnings("deprecation")
-    HashCode hc = Hashing.md5()
-        .newHasher(size)
-        .putBytes(container.data, container.sent, size)
-        .hash();
-    String md5 = BaseEncoding.base64().encode(hc.asBytes());
+    byte[] md5 = Hash.md5(container.data, container.sent, size);
+    String encodedMd5 = Util.base64(md5);
 
     final HashMap<String, RequestBody> params = new HashMap<>();
     params.putAll(upload.baseParams);
     params.put("part", Util.createStringPart(Integer.toString(container.num)));
     params.put("size", Util.createStringPart(Integer.toString(size)));
-    params.put("md5", Util.createStringPart(md5));
+    params.put("md5", Util.createStringPart(encodedMd5));
     if (upload.intel) {
       params.put("offset", Util.createStringPart(Integer.toString(container.sent)));
     }

src/main/java/com/filestack/internal/Util.java

@@ -1,17 +1,20 @@
 package com.filestack.internal;
 
 import com.filestack.HttpException;
-import java.io.File;
-import java.io.FileNotFoundException;
-import java.io.IOException;
-import java.io.InputStream;
-import java.util.Properties;
 import okhttp3.MultipartBody;
 import okhttp3.RequestBody;
 import okhttp3.ResponseBody;
 import okio.Buffer;
+import okio.ByteString;
 import retrofit2.Response;
 
+import javax.annotation.Nullable;
+import java.io.File;
+import java.io.FileNotFoundException;
+import java.io.IOException;
+import java.io.InputStream;
+import java.util.Properties;
+
 /**
  * Small helper functions that don't need their own class.
  */
@@ -137,7 +140,7 @@ public static boolean isUnitTest() {
   }
 
   /** Check if String is null or empty. */
-  public static boolean isNullOrEmpty(String value) {
+  public static boolean isNullOrEmpty(@Nullable String value) {
     return value == null || value.equals("");
   }
 
@@ -149,4 +152,17 @@ public static void throwIfNullOrEmpty(String value, String message) {
       throw new IllegalArgumentException(message);
     }
   }
+
+  public static String base64(byte[] data) {
+    return base64(data, 0, data.length);
+  }
+
+  public static String base64(byte[] data, int offset, int length) {
+    return ByteString.of(data, offset, length).base64();
+  }
+
+  public static String base64Url(byte[] data) {
+    return ByteString.of(data).base64Url();
+  }
+
 }

src/main/resources/META-INF/proguard/filestack.pro

@@ -35,10 +35,3 @@
 }
 # Guarded by a NoClassDefFoundError try/catch and only used when on the classpath.
 -dontwarn kotlin.Unit
-
-# Guava-specific rules
--dontwarn afu.org.checkerframework.**
--dontwarn org.checkerframework.**
--dontwarn com.google.errorprone.**
--dontwarn sun.misc.Unsafe
--dontwarn java.lang.ClassValue

src/test/java/com/filestack/TestFileLink.java

@@ -3,10 +3,11 @@
 import com.filestack.internal.BaseService;
 import com.filestack.internal.CdnService;
 import com.filestack.internal.Networking;
-import com.google.common.io.Files;
 import okhttp3.MediaType;
 import okhttp3.RequestBody;
 import okhttp3.ResponseBody;
+import okio.BufferedSink;
+import okio.Okio;
 import org.junit.After;
 import org.junit.Assert;
 import org.junit.Before;
@@ -91,12 +92,10 @@ public void testDownloadCustomFilename() throws Exception {
 
   @Test
   public void testOverwrite() throws Exception {
-    String pathname = "/tmp/filestack_test_filelink_overwrite.txt";
-    File file = new File(pathname);
-    if (!file.createNewFile()) {
-      Assert.fail("Unable to create resource");
-    }
-    Files.write("Test content".getBytes(), file);
+    File file = File.createTempFile("filestack", ".txt");
+    file.deleteOnExit();
+
+    Okio.buffer(Okio.sink(file)).writeUtf8("Test content").close();
 
     Mockito
         .doReturn(Helpers.createRawCall("application/json", ""))
@@ -107,11 +106,7 @@ public void testOverwrite() throws Exception {
     Config config = new Config("apiKey", "policy", "signature");
     FileLink fileLink = new FileLink(config, "handle");
 
-    fileLink.overwrite(pathname);
-
-    if (!file.delete()) {
-      Assert.fail("Unable to cleanup resource");
-    }
+    fileLink.overwrite(file.getAbsolutePath());
   }
 
   @Test

src/test/java/com/filestack/internal/HashTest.kt

@@ -0,0 +1,20 @@
+package com.filestack.internal
+
+import okio.ByteString
+import org.junit.Assert.assertEquals
+import org.junit.Test
+
+class HashTest {
+
+    @Test
+    fun md5() {
+        val result = Hash.md5("filestack".toByteArray())!!
+        assertEquals("4d9248e9ad027c6f03a90897e329ca92", ByteString.of(*result).hex())
+    }
+
+    @Test
+    fun hmacSha256() {
+        val result = Hash.hmacSha256("filestackKey".toByteArray(), "filestackMessage".toByteArray())
+        assertEquals("3ea0712eaae796f0330814eff179dd39ab852924a7af023789ce39e3788af2f3", result)
+    }
+}