WIP plugins: hook on client side

3 files changed, 141 insertions, 0 deletions

diff --git a/client/src/app/core/core.module.ts b/client/src/app/core/core.module.ts
index 06fa8fcf1..436c0dfb8 100644
--- a/client/src/app/core/core.module.ts
+++ b/client/src/app/core/core.module.ts
@@ -21,6 +21,7 @@ import { MessageService } from 'primeng/api'
 import { UserNotificationSocket } from '@app/core/notification/user-notification-socket.service'
 import { ServerConfigResolver } from './routing/server-config-resolver.service'
 import { UnloggedGuard } from '@app/core/routing/unlogged-guard.service'
+import { PluginService } from '@app/core/plugins/plugin.service'
 
 @NgModule({
   imports: [
@@ -61,6 +62,8 @@ import { UnloggedGuard } from '@app/core/routing/unlogged-guard.service'
     UserRightGuard,
     UnloggedGuard,
 
+    PluginService,
+
     RedirectService,
     Notifier,
     MessageService,
diff --git a/client/src/app/core/plugins/plugin.service.ts b/client/src/app/core/plugins/plugin.service.ts
new file mode 100644
index 000000000..6c567d3ca
--- /dev/null
+++ b/client/src/app/core/plugins/plugin.service.ts
@@ -0,0 +1,137 @@
+import { Injectable } from '@angular/core'
+import { Router } from '@angular/router'
+import { ServerConfigPlugin } from '@shared/models'
+import { ServerService } from '@app/core/server/server.service'
+import { ClientScript } from '@shared/models/plugins/plugin-package-json.model'
+import { PluginScope } from '@shared/models/plugins/plugin-scope.type'
+import { environment } from '../../../environments/environment'
+import { RegisterHookOptions } from '@shared/models/plugins/register.model'
+import { ReplaySubject } from 'rxjs'
+import { first } from 'rxjs/operators'
+
+interface HookStructValue extends RegisterHookOptions {
+  plugin: ServerConfigPlugin
+  clientScript: ClientScript
+}
+
+@Injectable()
+export class PluginService {
+  pluginsLoaded = new ReplaySubject<boolean>(1)
+
+  private plugins: ServerConfigPlugin[] = []
+  private scopes: { [ scopeName: string ]: { plugin: ServerConfigPlugin, clientScript: ClientScript }[] } = {}
+  private loadedScripts: { [ script: string ]: boolean } = {}
+
+  private hooks: { [ name: string ]: HookStructValue[] } = {}
+
+  constructor (
+    private router: Router,
+    private server: ServerService
+  ) {
+  }
+
+  initializePlugins () {
+    this.server.configLoaded
+      .subscribe(() => {
+        this.plugins = this.server.getConfig().plugins
+
+        this.buildScopeStruct()
+
+        this.pluginsLoaded.next(true)
+      })
+  }
+
+  ensurePluginsAreLoaded () {
+    return this.pluginsLoaded.asObservable()
+               .pipe(first())
+               .toPromise()
+  }
+
+  async loadPluginsByScope (scope: PluginScope) {
+    try {
+      await this.ensurePluginsAreLoaded()
+
+      const toLoad = this.scopes[ scope ]
+      if (!Array.isArray(toLoad)) return
+
+      const promises: Promise<any>[] = []
+      for (const { plugin, clientScript } of toLoad) {
+        if (this.loadedScripts[ clientScript.script ]) continue
+
+        promises.push(this.loadPlugin(plugin, clientScript))
+
+        this.loadedScripts[ clientScript.script ] = true
+      }
+
+      return Promise.all(promises)
+    } catch (err) {
+      console.error('Cannot load plugins by scope %s.', scope, err)
+    }
+  }
+
+  async runHook (hookName: string, param?: any) {
+    let result = param
+
+    const wait = hookName.startsWith('static:')
+
+    for (const hook of this.hooks[hookName]) {
+      try {
+        if (wait) result = await hook.handler(param)
+        else result = hook.handler()
+      } catch (err) {
+        console.error('Cannot run hook %s of script %s of plugin %s.', hookName, hook.plugin, hook.clientScript, err)
+      }
+    }
+
+    return result
+  }
+
+  private loadPlugin (plugin: ServerConfigPlugin, clientScript: ClientScript) {
+    const registerHook = (options: RegisterHookOptions) => {
+      if (!this.hooks[options.target]) this.hooks[options.target] = []
+
+      this.hooks[options.target].push({
+        plugin,
+        clientScript,
+        target: options.target,
+        handler: options.handler,
+        priority: options.priority || 0
+      })
+    }
+
+    console.log('Loading script %s of plugin %s.', clientScript.script, plugin.name)
+
+    const url = environment.apiUrl + `/plugins/${plugin.name}/${plugin.version}/client-scripts/${clientScript.script}`
+
+    return import(/* webpackIgnore: true */ url)
+      .then(script => script.register({ registerHook }))
+      .then(() => this.sortHooksByPriority())
+  }
+
+  private buildScopeStruct () {
+    for (const plugin of this.plugins) {
+      for (const key of Object.keys(plugin.clientScripts)) {
+        const clientScript = plugin.clientScripts[key]
+
+        for (const scope of clientScript.scopes) {
+          if (!this.scopes[scope]) this.scopes[scope] = []
+
+          this.scopes[scope].push({
+            plugin,
+            clientScript
+          })
+
+          this.loadedScripts[clientScript.script] = false
+        }
+      }
+    }
+  }
+
+  private sortHooksByPriority () {
+    for (const hookName of Object.keys(this.hooks)) {
+      this.hooks[hookName].sort((a, b) => {
+        return b.priority - a.priority
+      })
+    }
+  }
+}
diff --git a/client/src/app/core/server/server.service.ts b/client/src/app/core/server/server.service.ts
index 689f25a40..80c52164d 100644
--- a/client/src/app/core/server/server.service.ts
+++ b/client/src/app/core/server/server.service.ts
@@ -42,6 +42,7 @@ export class ServerService {
         css: ''
       }
     },
+    plugins: [],
     email: {
       enabled: false
     },