cf: allow for trailing slash on CF modpack page URL (#430)

Author: itzg

src/main/java/me/itzg/helpers/curseforge/InstallCurseForgeCommand.java

@@ -10,11 +10,10 @@
 import java.util.List;
 import java.util.Set;
 import java.util.concurrent.Callable;
-import java.util.regex.Matcher;
-import java.util.regex.Pattern;
 import java.util.stream.Collectors;
 import java.util.stream.Stream;
 import me.itzg.helpers.McImageHelper;
+import me.itzg.helpers.curseforge.ModpacksPageUrlParser.Parsed;
 import me.itzg.helpers.files.ResultsFileWriter;
 import me.itzg.helpers.files.TabularOutput;
 import me.itzg.helpers.http.PathOrUri;
@@ -161,27 +160,15 @@ static class Listed {
     @Option(names = "--missing-mods-filename", defaultValue = "MODS_NEED_DOWNLOAD.txt")
     String missingModsFilename;
 
-    private static final Pattern PAGE_URL_PATTERN = Pattern.compile(
-        "https://(www|beta)\\.curseforge\\.com/minecraft/modpacks/(?<slug>.+?)(/(files|download)(/(?<fileId>\\d+)?)?)?");
-
     @Override
     public Integer call() throws Exception {
         // https://www.curseforge.com/minecraft/modpacks/all-the-mods-8/files
         // https://www.curseforge.com/minecraft/modpacks/all-the-mods-8/files/4248390
 
         if (pageUrl != null) {
-            final Matcher m = PAGE_URL_PATTERN.matcher(pageUrl);
-            if (m.matches()) {
-                slug = m.group("slug");
-                final String fileIdStr = m.group("fileId");
-                if (fileIdStr != null) {
-                    fileId = Integer.parseInt(fileIdStr);
-                }
-            }
-            else {
-                System.err.println("Unexpected URL structure: "+pageUrl);
-                return ExitCode.USAGE;
-            }
+            final Parsed parsed = ModpacksPageUrlParser.parse(pageUrl);
+            slug = parsed.getSlug();
+            fileId = parsed.getFileId();
         }
 
         if (slug == null) {

src/main/java/me/itzg/helpers/curseforge/ModpacksPageUrlParser.java

@@ -0,0 +1,48 @@
+package me.itzg.helpers.curseforge;
+
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+import lombok.Builder;
+import lombok.Data;
+import me.itzg.helpers.errors.InvalidParameterException;
+import org.jetbrains.annotations.NotNull;
+
+class ModpacksPageUrlParser {
+    private static final Pattern PAGE_URL_PATTERN = Pattern.compile(
+        "https://(www|beta)\\.curseforge\\.com/minecraft/modpacks/(?<slug>[^/]+?)(/((files|download)(/(?<fileId>\\d+)?)?)?)?");
+
+    @Data @Builder
+    public static class Parsed {
+        String slug;
+        Integer fileId;
+    }
+
+    @NotNull
+    public static Parsed parse(String pageUrl) {
+        if (pageUrl == null) {
+            return Parsed.builder().build();
+        }
+
+        final Matcher m = PAGE_URL_PATTERN.matcher(pageUrl);
+        if (m.matches()) {
+            final String slug = m.group("slug");
+            final String fileIdStr = m.group("fileId");
+            if (fileIdStr != null) {
+                return Parsed.builder()
+                    .slug(slug)
+                    .fileId(Integer.parseInt(fileIdStr))
+                    .build();
+            }
+            else {
+                return Parsed.builder()
+                    .slug(slug)
+                    .build();
+            }
+        }
+        else {
+            throw new InvalidParameterException("Unexpected CF page URL structure: " + pageUrl);
+        }
+
+
+    }
+}

src/main/java/me/itzg/helpers/paper/PaperDownloadsClient.java

@@ -12,6 +12,9 @@
 import me.itzg.helpers.paper.model.VersionInfo;
 import reactor.core.publisher.Mono;
 
+/**
+ * <a href="https://api.papermc.io/docs/swagger-ui/index.html?configUrl=/openapi/swagger-config">Downloads API</a>
+ */
 public class PaperDownloadsClient implements AutoCloseable{
 
     private final UriBuilder uriBuilder;

src/test/java/me/itzg/helpers/curseforge/ModpacksPageUrlParserTest.java

@@ -0,0 +1,50 @@
+package me.itzg.helpers.curseforge;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
+
+import me.itzg.helpers.curseforge.ModpacksPageUrlParser.Parsed;
+import me.itzg.helpers.errors.InvalidParameterException;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.ValueSource;
+
+class ModpacksPageUrlParserTest {
+
+    @ParameterizedTest
+    @ValueSource(strings = {
+        "https://www.curseforge.com/minecraft/modpacks/create-perfect-world",
+        "https://beta.curseforge.com/minecraft/modpacks/create-perfect-world",
+        "https://www.curseforge.com/minecraft/modpacks/create-perfect-world/",
+        "https://www.curseforge.com/minecraft/modpacks/create-perfect-world/files",
+        "https://www.curseforge.com/minecraft/modpacks/create-perfect-world/files/",
+    })
+    void justSlug(String url) {
+        final Parsed parsed = ModpacksPageUrlParser.parse(url);
+        assertThat(parsed).isNotNull();
+        assertThat(parsed.getSlug()).isEqualTo("create-perfect-world");
+        assertThat(parsed.getFileId()).isNull();
+    }
+
+    @ParameterizedTest
+    @ValueSource(strings = {
+        "https://www.curseforge.com/minecraft/modpacks/create-perfect-world/files/5181367"
+    })
+    void slugAndFileId(String url) {
+        final Parsed parsed = ModpacksPageUrlParser.parse(url);
+        assertThat(parsed).isNotNull();
+        assertThat(parsed.getSlug()).isEqualTo("create-perfect-world");
+        assertThat(parsed.getFileId()).isEqualTo(5181367);
+    }
+
+    @ParameterizedTest
+    @ValueSource(strings = {
+        "",
+        "https://www.google.com",
+        "https://www.curseforge.com/minecraft/modpacks/create-perfect-world/wrong/",
+        "https://www.curseforge.com/minecraft/modpacks/create-perfect-world/invalid/5181367"
+    })
+    void invalid(String url) {
+        assertThatThrownBy(() -> ModpacksPageUrlParser.parse(url))
+            .isInstanceOf(InvalidParameterException.class);
+    }
+}