[FEATURE] Add a way to download dependencies

polymod/Polymod.hx

@@ -817,12 +817,17 @@ typedef ModContributor =
 };
 
 /**
- * A type representing a mod's dependencies.
- *
- * The map takes the mod's ID as the key and the required version as the value.
- * The version follows the Semantic Versioning format, with `*.*.*` meaning any version.
+ * A type representing a mod's dependency.
+ * The `version` field is the version of the dependency
+ * The `url` field is the Github Repository's url to download the dependency from
+ * The `commit` field is the commit hash of the dependency
  */
-typedef ModDependencies = Map<String, VersionRule>;
+typedef ModDependency = 
+{
+	version:VersionRule,
+	?url:String,
+	?commit:String
+};
 
 /**
  * A type representing data about a mod, as retrieved from its metadata file.
@@ -894,14 +899,14 @@ class ModMetadata
 	 * These other mods must be also be loaded in order for this mod to load,
 	 * and this mod must be loaded after the dependencies.
 	 */
-	public var dependencies:ModDependencies;
+	public var dependencies:Map<String, ModDependency>;
 
 	/**
 	 * A list of dependencies.
 	 * This mod must be loaded after the optional dependencies,
 	 * but those mods do not necessarily need to be loaded.
 	 */
-	public var optionalDependencies:ModDependencies;
+	public var optionalDependencies:Map<String, ModDependency>;
 
 	/**
 	 * A deprecated field representing the mod's author.
@@ -1014,8 +1019,8 @@ class ModMetadata
 		m.license = JsonHelp.str(json, 'license');
 		m.metadata = JsonHelp.mapStr(json, 'metadata');
 
-		m.dependencies = JsonHelp.mapVersionRule(json, 'dependencies');
-		m.optionalDependencies = JsonHelp.mapVersionRule(json, 'optionalDependencies');
+		m.dependencies = JsonHelp.mapModDependency(json, 'dependencies');
+		m.optionalDependencies = JsonHelp.mapModDependency(json, 'optionalDependencies');
 
 		return m;
 	}
@@ -1166,6 +1171,11 @@ enum abstract PolymodErrorCode(String) from String to String
 	 */
 	var DEPENDENCY_CHECK_SKIPPED:String = 'dependency_check_skipped';
 
+	/**
+	 * Polymod attempted to download a mod, but it failed to do so.
+	 */
+	var DEPENDENCY_NOT_DOWNLOADABLE:String = 'dependency_not_downloadable';
+
 	/**
 	 * The given mod's API version does not match the version rule passed to Polymod.init.
 	 * - This generally indicates the mod is outdated and should be updated by the author.

polymod/format/JsonHelp.hx

@@ -1,5 +1,6 @@
 package polymod.format;
 
+import polymod.Polymod.ModDependency;
 import thx.semver.VersionRule;
 
 class JsonHelp
@@ -89,6 +90,25 @@ class JsonHelp
 		return map;
 	}
 
+	public static function mapModDependency(json:Dynamic, field:String):Map<String, ModDependency>
+		{
+			var map:Map<String, ModDependency> = new Map<String, ModDependency>();
+			if (json == null || field == '' || field == null)
+				return map;
+			var val = null;
+			if (Reflect.hasField(json, field))
+				val = Reflect.field(json, field);
+			if (val != null)
+			{
+				for (field in Reflect.fields(val))
+				{
+					var fieldVal = Reflect.field(val, field);
+					map.set(field, fieldVal);
+				}
+			}
+			return map;
+		}
+
 	public static function str(json:Dynamic, field:String, defaultValue:String = ''):String
 	{
 		var str:String = '';

polymod/util/DependencyUtil.hx

@@ -1,7 +1,12 @@
 package polymod.util;
 
-import polymod.Polymod.ModDependencies;
+import haxe.Http;
+import haxe.io.Bytes;
+import haxe.zip.Reader;
+import polymod.Polymod.ModDependency;
 import polymod.Polymod.ModMetadata;
+import sys.FileSystem;
+import sys.io.File;
 import thx.semver.VersionRule;
 
 /**
@@ -53,7 +58,7 @@ class DependencyUtil
 		var result:Array<ModMetadata> = [];
 
 		// Compile a map of mod dependencies.
-		var deps:ModDependencies = compileDependencies(modList);
+		var deps:Map<String, ModDependency> = compileDependencies(modList);
 
 		// Check that all mods are in the mod list.
 		var relevantMods:Array<ModMetadata> = [];
@@ -68,7 +73,7 @@ class DependencyUtil
 		// Check that all dependencies are satisfied.
 		for (dep in deps.keys())
 		{
-			var depRule:VersionRule = deps.get(dep);
+			var depRule:VersionRule = deps.get(dep).version;
 
 			// Check that the dependency is in the mod list.
 			var depMod:ModMetadata = null;
@@ -112,7 +117,7 @@ class DependencyUtil
 	static function validateDependencies(modList:Array<ModMetadata>):Bool
 	{
 		// Compile a map of mod dependencies.
-		var deps:ModDependencies = compileDependencies(modList);
+		var deps:Map<String, ModDependency> = compileDependencies(modList);
 
 		// Check that all mods are in the mod list.
 		var relevantMods:Array<ModMetadata> = [];
@@ -127,7 +132,7 @@ class DependencyUtil
 		// Check that all dependencies are satisfied.
 		for (dep in deps.keys())
 		{
-			var depRule:VersionRule = deps.get(dep);
+			var depRule:VersionRule = deps.get(dep).version;
 
 			// Check that the dependency is in the mod list.
 			var depMod:ModMetadata = null;
@@ -307,33 +312,124 @@ class DependencyUtil
 	 * For example, if one mod requires `>1.2.0` of `modA` and another requires `>1.3.0` of `modA`,
 	 * the merged list will be `[modA: '>1.2.0 && >1.3.0']`.
 	 */
-	public static function compileDependencies(modList:Array<ModMetadata>):Map<String, VersionRule>
+	public static function compileDependencies(modList:Array<ModMetadata>):Map<String, ModDependency>
 	{
-		var result:Map<String, VersionRule> = [];
+		var result:Map<String, ModDependency> = [];
 
 		for (mod in modList)
 		{
 			if (result[mod.id] == null)
-				result[mod.id] = VersionUtil.DEFAULT_VERSION_RULE;
+				result[mod.id] = {
+					version: VersionUtil.DEFAULT_VERSION_RULE
+				};
 
 			if (mod.dependencies != null)
 			{
 				for (dependencyId in mod.dependencies.keys())
 				{
-					var dependencyRule:VersionRule = mod.dependencies[dependencyId];
+					if (result[dependencyId] == null)
+						result[dependencyId] = {
+							version: VersionUtil.DEFAULT_VERSION_RULE
+						};
 
-					if (result[dependencyId] != null)
+					result[dependencyId].url = mod.dependencies[dependencyId].url;
+					result[dependencyId].commit = mod.dependencies[dependencyId].commit;
+					var dependencyRule:VersionRule = mod.dependencies[dependencyId].version;
+
+					if (result[dependencyId].version != null)
 					{
-						result[dependencyId] = VersionUtil.combineRulesAnd(result[dependencyId], dependencyRule);
+						result[dependencyId].version = VersionUtil.combineRulesAnd(result[dependencyId].version, dependencyRule);
 					}
 					else
 					{
-						result[dependencyId] = dependencyRule;
+						result[dependencyId].version = dependencyRule;
 					}
 				}
 			}
 		}
 
 		return result;
 	}
+
+	/**
+	 * Given a github url and commit hash, download the dependency.
+	 * This is done using an http request.
+	 * @param outputDir the directory to download the dependency to
+	 * @param url github repository url: https://github.com/OWNER/REPOSITORY
+	 * @param commit commit hash 
+	 */
+	public static function downloadDependency(outputDir:String, url:String, commit:String):Void
+	{
+		var zipBytes:Null<Bytes> = getDependencyAsZip(url, commit);
+
+		if (zipBytes == null || zipBytes.length == 0)
+			return;
+
+		var reader = new Reader(new haxe.io.BytesInput(zipBytes));
+		var entries = reader.read();
+
+		if (!FileSystem.exists(outputDir))
+		{
+			FileSystem.createDirectory(outputDir);
+		}
+
+		for (entry in entries)
+		{
+			var fileName = entry.fileName;
+			if (entry.fileSize > 0)
+			{
+				var content = entry.data;
+				var filePath = outputDir + "/" + fileName;
+
+				var dirs = fileName.split("/");
+				dirs.pop();
+				var currentDir = outputDir;
+				for (dir in dirs)
+				{
+					currentDir += "/" + dir;
+					if (!FileSystem.exists(currentDir))
+					{
+						FileSystem.createDirectory(currentDir);
+					}
+				}
+
+				File.saveBytes(filePath, content);
+				trace("Extracted: " + filePath);
+			}
+		}
+
+		trace("Extraction complete. Files saved in: " + outputDir);
+	}
+
+	/**
+	 * Get the bytes of a dependency as a zip file.
+	 * @param url github repository url: https://github.com/OWNER/REPOSITORY
+	 * @param commit commit hash 
+	 * @return Null<Bytes>
+	 */
+	public static function getDependencyAsZip(url:String, commit:String):Null<Bytes>
+	{
+		// url structure of the code to download
+		// https://codeload.github.com/OWNER/REPOSITORY/zip/COMMIT
+
+		var urlSplit = url.split('/');
+		var repository = urlSplit[urlSplit.length - 1];
+		var owner = urlSplit[urlSplit.length - 2];
+
+		var downloadUrl = 'https://codeload.github.com/${owner}/${repository}/zip/${commit}';
+
+		var zipBytes:Null<Bytes> = null;
+
+		var http = new Http(downloadUrl);
+		http.onBytes = function(bytes:Bytes)
+		{
+			zipBytes = bytes;
+		}
+		http.request(false);
+
+		if (zipBytes == null || zipBytes.length == 0)
+			Polymod.error(DEPENDENCY_NOT_DOWNLOADABLE, 'Failed to download dependency: ${downloadUrl}');
+
+		return zipBytes;
+	}
 }