softwaremill · wkromolicki · Apr 10, 2017 · May 5, 2017 · May 5, 2017
diff --git a/build.gradle b/build.gradle
@@ -13,17 +13,7 @@ repositories {
 }
 
 dependencies {
-    compile 'io.javaslang:javaslang:2.0.2'
+    compile group: 'io.javaslang', name: 'javaslang', version: '2.0.5'
     compile 'org.jsoup:jsoup:1.10.2'
-
-    compile 'org.slf4j:slf4j-api:1.6.4'
-    compile 'ch.qos.logback:logback-classic:1.0.1'
-    compile 'ch.qos.logback:logback-core:1.0.1'
-
-    compileOnly "org.projectlombok:lombok:1.16.10"
-
-    testCompile 'org.spockframework:spock-core:1.0-groovy-2.4'
-    testCompile 'org.codehaus.groovy:groovy:2.4.7'
-    testCompile 'cglib:cglib:3.2.2'
 
 }
diff --git a/src/main/java/com/softwaremill/java_fp_example/FacebookImageVersion0.java b/src/main/java/com/softwaremill/java_fp_example/FacebookImageVersion0.java
diff --git a/src/main/java/com/softwaremill/java_fp_example/FacebookImageVersion1MoreObjectOriented.java b/src/main/java/com/softwaremill/java_fp_example/FacebookImageVersion1MoreObjectOriented.java
diff --git a/src/main/java/com/softwaremill/java_fp_example/FacebookImageVersion2Javaslang.java b/src/main/java/com/softwaremill/java_fp_example/FacebookImageVersion2Javaslang.java
diff --git a/src/main/java/com/softwaremill/java_fp_example/FacebookImageVersion3BetterJavaslang.java b/src/main/java/com/softwaremill/java_fp_example/FacebookImageVersion3BetterJavaslang.java
diff --git a/src/main/java/com/softwaremill/java_fp_example/contest/wkromolicki/FacebookImage.java b/src/main/java/com/softwaremill/java_fp_example/contest/wkromolicki/FacebookImage.java
@@ -0,0 +1,36 @@
+package com.softwaremill.java_fp_example.contest.wkromolicki;
+
+import static com.softwaremill.java_fp_example.DefaultImage.DEFAULT_IMAGE;
+import static com.softwaremill.java_fp_example.contest.wkromolicki.ParserFunctions.*;
+
+import java.util.function.Consumer;
+import java.util.function.Function;
+import java.util.function.Predicate;
+
+import org.jsoup.nodes.Element;
+
+import javaslang.control.Try;
+
+public class FacebookImage {
+
+    private final static Predicate<Element> FACEBOOK_IMAGE_TAG_FILTER = el -> "og:image".equals(el.attr("property"));
+
+    public static String extractImage(String pageUrl) {
+        return findImage.apply(FACEBOOK_IMAGE_TAG_FILTER)
+                .apply(pageUrl)
+                .onFailure(handleExceptionFor(pageUrl))
+                .getOrElse(DEFAULT_IMAGE);
+    }
+
+    private static Function<Predicate<Element>, Function<String, Try<String>>> findImage =
+       filter -> fetchUrl.andThen(lift(parseUrl)).andThen(lift(findMetaTag.apply(filter))).andThen(lift(extractContent));
+
+
+    private static Consumer<Throwable> handleExceptionFor(String pageUrl) {
+        return e -> log(String.format("Unable to extract og:image from url %s. Problem: %s", pageUrl, e.getMessage()));
+    }
+
+    private static void log(String message) {
+        System.out.println(message);
+    }
+}
diff --git a/src/main/java/com/softwaremill/java_fp_example/contest/wkromolicki/FacebookImageVersion.java b/src/main/java/com/softwaremill/java_fp_example/contest/wkromolicki/FacebookImageVersion.java
@@ -0,0 +1,53 @@
+package com.softwaremill.java_fp_example.contest.wkromolicki;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.net.HttpURLConnection;
+import java.net.URL;
+import java.nio.charset.StandardCharsets;
+import java.util.Scanner;
+import java.util.logging.Logger;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+import java.util.zip.GZIPInputStream;
+
+public class FacebookImageVersion {
+
+    public static final String DEFAULT_IMAGE = "https://softwaremill.com/images/logo-vertical.023d8496.png";
+    private static final Pattern FACEBOOK_IMAGE_PATTERN = Pattern.compile("<head>.*?(<meta\\s+[^>]*?property=\"og:image\".*?\\/?>).*?<\\/head>", Pattern.CASE_INSENSITIVE | Pattern.DOTALL | Pattern.MULTILINE);
+    private static final Pattern TAG_CONTENT_PATTERN = Pattern.compile("content=\"(.+?)\"", Pattern.CASE_INSENSITIVE | Pattern.DOTALL | Pattern.MULTILINE);
+    private static final int TEN_SECONDS = 10_000;
+    private static final Logger log = Logger.getLogger(FacebookImageVersion.class.getName());
+
+    public static String extractImageAddressFrom(String pageUrl) {
+        HttpURLConnection c = null;
+        try {
+            c = (HttpURLConnection) new URL(pageUrl).openConnection();
+        } catch (IOException e) {
+            log.severe("Cannot open connection to " + pageUrl + " - reason: " + e.toString());
+            return DEFAULT_IMAGE;
+        }
+        c.setConnectTimeout(TEN_SECONDS);
+        c.setReadTimeout(TEN_SECONDS);
+        String contentEncoding = c.getHeaderField("Content-Encoding");
+        String html = null;
+        try (InputStream is = contentEncoding != null && contentEncoding.contains("gzip") ? new GZIPInputStream(c.getInputStream()) : c.getInputStream();
+             Scanner s = new Scanner(is, StandardCharsets.UTF_8.name())) {
+            html = s.useDelimiter("\\A").next();
+        } catch (IOException e) {
+            log.severe("Cannot read from " + pageUrl + " - reason: " + e.toString());
+            return DEFAULT_IMAGE;
+        }
+        try {
+            Matcher tagMatch = FACEBOOK_IMAGE_PATTERN.matcher(html);
+            tagMatch.find();
+            Matcher contentMatch = TAG_CONTENT_PATTERN.matcher(tagMatch.group(1));
+            contentMatch.find();
+            return contentMatch.group(1);
+        } catch (Exception e) {
+            log.warning("No og:image found for blog post " + pageUrl);
+            return DEFAULT_IMAGE;
+        }
+    }
+
+}
diff --git a/...st/your_github_login/LICENSE-template.txt → ...p_example/contest/wkromolicki/LICENSE.txt b/...st/your_github_login/LICENSE-template.txt → ...p_example/contest/wkromolicki/LICENSE.txt
@@ -1,6 +1,6 @@
 MIT License
 
-Copyright (c) 2017 <twój login na GitHubie>
+Copyright (c) 2017 wkromolicki
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal

diff --git a/src/main/java/com/softwaremill/java_fp_example/contest/wkromolicki/ParserFunctions.java b/src/main/java/com/softwaremill/java_fp_example/contest/wkromolicki/ParserFunctions.java
@@ -0,0 +1,38 @@
+package com.softwaremill.java_fp_example.contest.wkromolicki;
+
+import java.net.URL;
+import java.util.function.Function;
+import java.util.function.Predicate;
+
+import org.jsoup.Jsoup;
+import org.jsoup.nodes.Document;
+import org.jsoup.nodes.Element;
+
+import javaslang.collection.List;
+import javaslang.control.Try;
+
+public class ParserFunctions {
+    public final static int TIMEOUT = 10_000;
+
+    public static Function<Predicate<Element>, Function<Document, Try<Element>>> findMetaTag =
+            tagFilter -> document -> List.ofAll(document.head().getElementsByTag("meta")).filter(tagFilter).headOption().toTry();
+
+
+    public static Function<Element, Try<String>> extractContent = safe(el -> el.attr("content"));
+
+    public static Function<String, Try<URL>> fetchUrl = safe(URL::new);
+
+    public static Function<URL, Try<Document>> parseUrl = safe(url -> Jsoup.parse(url, TIMEOUT));
+
+
+    //below are helper methods which do not belong to parser domain and should be in some library
+    public static <A,B> Function<Try<A>, Try<B>> lift(Function<A, Try<B>> func) {
+        return in -> in.flatMap(func::apply);
+    }
+
+    public static <A, B> Function<A, Try<B>> safe(Try.CheckedFunction<A, B> func) {
+        return a -> Try.of(() -> func.apply(a));
+    }
+
+
+}
diff --git a/...mple/contest/your_github_login/Readme.txt → ...fp_example/contest/wkromolicki/Readme.txt b/...mple/contest/your_github_login/Readme.txt → ...fp_example/contest/wkromolicki/Readme.txt