Manga Ship extension, DataImageInterceptor (#3177)

* Manga Ship extension, DataImageInterceptor

* tweak regex

lib/dataimage/build.gradle

@@ -0,0 +1,30 @@
+apply plugin: 'com.android.library'
+apply plugin: 'kotlin-android'
+
+android {
+    compileSdkVersion 27
+    buildToolsVersion '29.0.3'
+
+    defaultConfig {
+        minSdkVersion 16
+        targetSdkVersion 27
+        versionCode 1
+        versionName '1.0.0'
+    }
+
+    buildTypes {
+        release {
+            minifyEnabled false
+        }
+    }
+}
+
+repositories {
+    mavenCentral()
+}
+
+dependencies {
+    compileOnly "org.jetbrains.kotlin:kotlin-stdlib:$kotlin_version"
+    compileOnly 'com.squareup.okhttp3:okhttp:3.10.0'
+    compileOnly 'org.jsoup:jsoup:1.13.1'
+}

lib/dataimage/src/main/AndroidManifest.xml

@@ -0,0 +1,2 @@
+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+    package="eu.kanade.tachiyomi.lib.dataimage" />

lib/dataimage/src/main/java/eu/kanade/tachiyomi/lib/dataimage/DataImageInterceptor.kt

@@ -0,0 +1,65 @@
+package eu.kanade.tachiyomi.lib.dataimage
+
+import android.util.Base64
+import okhttp3.Interceptor
+import okhttp3.MediaType
+import okhttp3.Protocol
+import okhttp3.Response
+import okhttp3.ResponseBody
+import org.jsoup.nodes.Element
+
+/**
+ * If a source provides images via a data:image string instead of a URL, use these functions and interceptor
+ */
+
+/**
+ * Use if the attribute tag could have a data:image string or URL
+ * Transforms data:image in to a fake URL that OkHttp won't die on
+ */
+fun Element.dataImageAsUrl(attr: String): String {
+    return if (this.attr(attr).startsWith("data")) {
+        "https://127.0.0.1/?" + this.attr(attr).substringAfter(":")
+    } else {
+        this.attr("abs:$attr")
+    }
+}
+
+/**
+ * Use if the attribute tag has a data:image string but real URLs are on a different attribute
+ */
+fun Element.dataImageAsUrlOrNull(attr: String): String? {
+    return if (this.attr(attr).startsWith("data")) {
+        "https://127.0.0.1/?" + this.attr(attr).substringAfter(":")
+    } else {
+        null
+    }
+}
+
+/**
+ * Interceptor that detects the URLs we created with the above functions, base64 decodes the data if necessary,
+ * and builds a response with a valid image that Tachiyomi can display
+ */
+class DataImageInterceptor : Interceptor {
+    private val mediaTypePattern = Regex("""(^[^;,]*)[;,]""")
+
+    override fun intercept(chain: Interceptor.Chain): Response {
+        val url = chain.request().url().toString()
+        return if (url.startsWith("https://127.0.0.1/?image")) {
+            val dataString = url.substringAfter("?")
+            val byteArray = if (dataString.contains("base64")) {
+                Base64.decode(dataString.substringAfter("base64,"), Base64.DEFAULT)
+            } else {
+                dataString.substringAfter(",").toByteArray()
+            }
+            val mediaType = MediaType.parse(mediaTypePattern.find(dataString)!!.value)
+            Response.Builder().body(ResponseBody.create(mediaType, byteArray))
+                .request(chain.request())
+                .protocol(Protocol.HTTP_1_0)
+                .code(200)
+                .message("")
+                .build()
+        } else {
+            chain.proceed(chain.request())
+        }
+    }
+}