add universal path classes, refactor view engine to use them

lib/src/support/UniversalPath.ts

@@ -0,0 +1,90 @@
+import { path as deno_path } from '../external/std.ts'
+
+export enum UniversalPathPrefix {
+    HTTP = 'http://',
+    HTTPS = 'https://',
+    Local = 'file://',
+}
+
+export type PathLike = string | UniversalPath
+
+export function universal_path(...parts: PathLike[]): UniversalPath {
+    let [main, ...concats] = parts
+    if ( !(main instanceof UniversalPath) ) main = new UniversalPath(main)
+    return main.concat(...concats)
+}
+
+export class UniversalPath {
+    protected _prefix!: UniversalPathPrefix
+    protected _local!: string
+
+    constructor(
+        protected readonly initial: string,
+    ) {
+        this.set_prefix()
+        this.set_local()
+    }
+
+    protected set_prefix() {
+        if ( this.initial.toLowerCase().startsWith('http://') ) {
+            this._prefix = UniversalPathPrefix.HTTP
+        } else if ( this.initial.toLowerCase().startsWith('https://') ) {
+            this._prefix = UniversalPathPrefix.HTTPS
+        } else {
+            this._prefix = UniversalPathPrefix.Local
+        }
+    }
+
+    protected set_local() {
+        this._local = this.initial
+        if ( this.initial.toLowerCase().startsWith(this._prefix) ) {
+            this._local = this._local.slice(this._prefix.length)
+        }
+
+        if ( this._prefix === UniversalPathPrefix.Local && !this._local.startsWith('/') ) {
+            this._local = deno_path.resolve(this._local)
+        }
+    }
+
+    get prefix() {
+        return this._prefix
+    }
+
+    get is_local() {
+        return this._prefix === UniversalPathPrefix.Local
+    }
+
+    get is_remote() {
+        return this._prefix !== UniversalPathPrefix.Local
+    }
+
+    get unqualified() {
+        return this._local
+    }
+
+    get to_local() {
+        if ( this.is_local ) {
+            return this._local
+        } else {
+            return `${this.prefix}${this._local}`
+        }
+    }
+
+    get to_remote() {
+        return `${this.prefix}${this._local}`
+    }
+
+    public concat(...paths: PathLike[]): UniversalPath {
+        const resolved = deno_path.join(this.unqualified, ...(paths.map(p => typeof p === 'string' ? p : p.unqualified)))
+        return new UniversalPath(`${this.prefix}${resolved}`)
+    }
+
+    public append(path: PathLike): this {
+        this._local += String(path)
+        return this
+    }
+
+    toString() {
+        return `${this.prefix}${this._local}`
+    }
+}

lib/src/unit/ViewEngine.ts

@@ -5,7 +5,8 @@ import {views, handlebars} from '../external/http.ts'
 import {Unit} from '../lifecycle/decorators.ts'
 import {Logging} from '../service/logging/Logging.ts'
 import {ConfigError} from '../error/ConfigError.ts'
-import {path, fs} from '../external/std.ts'
+import {fs} from '../external/std.ts'
+import {PathLike, universal_path, UniversalPath} from '../support/UniversalPath.ts'
 
 /**
  * Error thrown when an action requiring a view engine is attempted, but no view
@@ -35,7 +36,7 @@ export class MissingTemplateDirectoryError extends Error {
 @Unit()
 export default class ViewEngine extends LifecycleUnit {
     protected engine?: Types
-    protected template_dir?: string
+    protected template_dir?: UniversalPath
 
     constructor(
         protected readonly config: Config,
@@ -56,7 +57,7 @@ export default class ViewEngine extends LifecycleUnit {
             throw new ConfigError('app.views.base_dir', base_dir)
         }
 
-        this.template_dir = this.app.app_path(base_dir)
+        this.template_dir = universal_path(this.app.app_path(base_dir))
         this.engine = config
         this.logger.info(`Determined view engine from config: ${config}`)
         this.logger.info(`Determined base directory for templates: ${this.template_dir}`)
@@ -71,16 +72,14 @@ export default class ViewEngine extends LifecycleUnit {
      * @return Promise<string>
      */
     public async template(template_path: string, data: { [key: string]: any } = {}) {
-        let file_path = `${this.template_path(template_path.replace(/:/g, '/'))}${this.get_file_extension()}`
-        if ( file_path.startsWith('file://') ) {
-            file_path = file_path.slice(7)
-        }
+        const template_name = template_path.replace(/:/g, '/')
+        const file_path = this.template_path(template_name).append(this.get_file_extension())
 
         this.logger.debug(`Rendering template "${template_path}" from file: ${file_path}`)
 
         // TODO cache this
         // TODO replace with fs.readFileStr
-        const content = await Deno.readTextFile(file_path)
+        const content = await Deno.readTextFile(file_path.to_local)
         const engine: views.Engine = this.get_engine()
 
         return engine(
@@ -96,17 +95,9 @@ export default class ViewEngine extends LifecycleUnit {
      * @param {...string} parts
      * @return string
      */
-    public template_path(...parts: string[]): string {
+    public template_path(...parts: PathLike[]): UniversalPath {
         if ( !this.template_dir ) throw new MissingTemplateDirectoryError()
-        let template_dir = this.template_dir
-        if ( template_dir.startsWith('file://') ) template_dir = template_dir.slice(7)
-
-        const resolved_path = path.resolve(template_dir, ...parts)
-        if ( resolved_path.startsWith('/') ) {
-            return `file://${resolved_path}`
-        } else {
-            return resolved_path
-        }
+        return this.template_dir.concat(...parts)
     }
 
     /**
@@ -156,13 +147,11 @@ export default class ViewEngine extends LifecycleUnit {
      */
     public get_render_context() {
         if ( !this.template_dir ) throw new MissingTemplateDirectoryError()
-        let template_dir = this.template_dir
-        if ( template_dir.startsWith('file://') ) template_dir = template_dir.slice(7)
 
         return {
             viewExt: this.get_file_extension(),
             viewEngine: this.get_engine(),
-            viewRoot: template_dir,
+            viewRoot: this.template_dir.to_local,
             useCache: false, // TODO better value here
             cache: undefined,
         }
@@ -184,14 +173,10 @@ export default class ViewEngine extends LifecycleUnit {
     protected async init_engine_handlebars() {
         const partials_dir: unknown = this.config.get('app.views.partials_dir')
         if ( String(partials_dir) ) {
-            let partials_path = this.template_path(String(partials_dir))
+            const partials_path = this.template_path(String(partials_dir))
             this.logger.info(`Registering Handlebars partials from: ${partials_path}`)
 
-            if ( partials_path.startsWith('file://') ) {
-                partials_path = partials_path.slice(7)
-            }
-
-            for await ( const entry of fs.walk(partials_path) ) {
+            for await ( const entry of fs.walk(partials_path.to_local) ) {
                 if ( !entry.isFile || !entry.path.endsWith(this.get_file_extension()) ) {
                     if ( entry.isFile ) this.logger.debug(`Skipping file in Handlebars partials path with invalid suffix: ${entry.path}`)
                     continue