MediaBackend: Add WebdavBackend

Signed-off-by: Philip Molares <philip.molares@udo.edu>

src/media/backends/webdav-backend.ts

@@ -0,0 +1,139 @@
+/*
+ * SPDX-FileCopyrightText: 2021 The HedgeDoc developers (see AUTHORS file)
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+import { Inject, Injectable } from '@nestjs/common';
+import mediaConfiguration from '../../config/media.config';
+import { ConsoleLoggerService } from '../../logger/console-logger.service';
+import { MediaBackend } from '../media-backend.interface';
+import { BackendData } from '../media-upload.entity';
+import { MediaConfig } from '../../config/media.config';
+import { MediaBackendError } from '../../errors/errors';
+import { BackendType } from './backend-type.enum';
+import fetch, { Response } from 'node-fetch';
+
+@Injectable()
+export class WebdavBackend implements MediaBackend {
+  private config: MediaConfig['backend']['webdav'];
+  private authHeader: string;
+  private baseUrl: string;
+
+  constructor(
+    private readonly logger: ConsoleLoggerService,
+    @Inject(mediaConfiguration.KEY)
+    private mediaConfig: MediaConfig,
+  ) {
+    this.logger.setContext(WebdavBackend.name);
+    if (mediaConfig.backend.use === BackendType.WEBDAV) {
+      this.config = mediaConfig.backend.webdav;
+      const url = new URL(this.config.connectionString);
+      const port = url.port !== '' ? `:${url.port}` : '';
+      this.baseUrl = `${url.protocol}//${url.hostname}${port}${url.pathname}`;
+      if (this.config.uploadDir && this.config.uploadDir !== '') {
+        this.baseUrl = WebdavBackend.joinURL(
+          this.baseUrl,
+          this.config.uploadDir,
+        );
+      }
+      this.authHeader = WebdavBackend.generateBasicAuthHeader(
+        url.username,
+        url.password,
+      );
+      fetch(this.baseUrl, {
+        method: 'PROPFIND',
+        headers: {
+          Accept: 'text/plain', // eslint-disable-line @typescript-eslint/naming-convention
+          Authorization: this.authHeader, // eslint-disable-line @typescript-eslint/naming-convention
+          Depth: '0', // eslint-disable-line @typescript-eslint/naming-convention
+        },
+      })
+        .then((response) => {
+          if (!response.ok) {
+            throw new Error(`Can't access ${this.baseUrl}`);
+          }
+        })
+        .catch(() => {
+          throw new Error(`Can't access ${this.baseUrl}`);
+        });
+    }
+  }
+
+  async saveFile(
+    buffer: Buffer,
+    fileName: string,
+  ): Promise<[string, BackendData]> {
+    try {
+      const contentLength = buffer.length;
+      await fetch(WebdavBackend.joinURL(this.baseUrl, '/', fileName), {
+        method: 'PUT',
+        body: buffer,
+        headers: {
+          Authorization: this.authHeader, // eslint-disable-line @typescript-eslint/naming-convention
+          'Content-Type': 'application/octet-stream', // eslint-disable-line @typescript-eslint/naming-convention
+          'Content-Length': `${contentLength}`, // eslint-disable-line @typescript-eslint/naming-convention
+          // eslint-disable-next-line @typescript-eslint/naming-convention
+          'If-None-Match': '*', // Don't overwrite already existing files
+        },
+      }).then((res) => WebdavBackend.checkStatus(res));
+      this.logger.log(`Uploaded file ${fileName}`, 'saveFile');
+      return [this.getUrl(fileName), null];
+    } catch (e) {
+      this.logger.error((e as Error).message, (e as Error).stack, 'saveFile');
+      throw new MediaBackendError(`Could not save '${fileName}' on WebDav`);
+    }
+  }
+
+  async deleteFile(fileName: string, _: BackendData): Promise<void> {
+    try {
+      await fetch(WebdavBackend.joinURL(this.baseUrl, '/', fileName), {
+        method: 'DELETE',
+        headers: {
+          // eslint-disable-next-line @typescript-eslint/naming-convention
+          Authorization: this.authHeader,
+        },
+      }).then((res) => WebdavBackend.checkStatus(res));
+      const url = this.getUrl(fileName);
+      this.logger.log(`Deleted ${url}`, 'saveFile');
+      return;
+    } catch (e) {
+      this.logger.error((e as Error).message, (e as Error).stack, 'saveFile');
+      throw new MediaBackendError(`Could not delete '${fileName}' on WebDav`);
+    }
+  }
+
+  private getUrl(fileName: string): string {
+    return WebdavBackend.joinURL(this.config.publicUrl, '/', fileName);
+  }
+
+  private static generateBasicAuthHeader(
+    username: string,
+    password: string,
+  ): string {
+    const encoded = Buffer.from(`${username}:${password}`).toString('base64');
+    return `Basic ${encoded}`;
+  }
+
+  private static joinURL(...urlParts: Array<string>): string {
+    return urlParts.reduce((output, next, index) => {
+      if (
+        index === 0 ||
+        next !== '/' ||
+        (next === '/' && output[output.length - 1] !== '/')
+      ) {
+        output += next;
+      }
+      return output;
+    }, '');
+  }
+
+  private static checkStatus(res: Response): Response {
+    if (res.ok) {
+      // res.status >= 200 && res.status < 300
+      return res;
+    } else {
+      throw new MediaBackendError(res.statusText);
+    }
+  }
+}

src/media/media.module.ts

@@ -16,6 +16,7 @@ import { MediaService } from './media.service';
 import { S3Backend } from './backends/s3-backend';
 import { ImgurBackend } from './backends/imgur-backend';
 import { AzureBackend } from './backends/azure-backend';
+import { WebdavBackend } from './backends/webdav-backend';
 
 @Module({
   imports: [
@@ -31,6 +32,7 @@ import { AzureBackend } from './backends/azure-backend';
     AzureBackend,
     ImgurBackend,
     S3Backend,
+    WebdavBackend,
   ],
   exports: [MediaService],
 })

src/media/media.service.ts

@@ -25,6 +25,7 @@ import { ImgurBackend } from './backends/imgur-backend';
 import { User } from '../users/user.entity';
 import { MediaUploadDto } from './media-upload.dto';
 import { Note } from '../notes/note.entity';
+import { WebdavBackend } from './backends/webdav-backend';
 
 @Injectable()
 export class MediaService {
@@ -203,6 +204,8 @@ export class MediaService {
         return BackendType.IMGUR;
       case 's3':
         return BackendType.S3;
+      case 'webdav':
+        return BackendType.WEBDAV;
     }
   }
 
@@ -216,6 +219,8 @@ export class MediaService {
         return this.moduleRef.get(AzureBackend);
       case BackendType.IMGUR:
         return this.moduleRef.get(ImgurBackend);
+      case BackendType.WEBDAV:
+        return this.moduleRef.get(WebdavBackend);
     }
   }