Initial commit of akmon project

utils/mediaCacheService.uts

@@ -0,0 +1,158 @@
+export type MediaCacheIndex =UTSJSONObject
+
+type DownloadFileResult = {
+  statusCode?: number
+  tempFilePath?: string
+  tempFilePathArray?: string[]
+  apFilePath?: string
+  // UTS不支持索引签名，已移除
+}
+export class MediaCacheService {
+  static STORAGE_KEY: string = 'media-cache-index'
+  static index: MediaCacheIndex | null = null
+
+  static async init(): Promise<void> {
+    if (this.index != null) return
+    try {
+      const res = await new Promise<UTSJSONObject | null>((resolve) => {
+          uni.getStorage({
+            key: this.STORAGE_KEY,
+              success: (result) => {
+                const json = result.data as UTSJSONObject
+                const data = json['data'] as UTSJSONObject | null
+                resolve(data)
+            },
+            fail: () => resolve(null)
+          })
+      })
+      if (res != null) {
+        this.index = res
+      } else {
+        this.index = {}
+      }
+    } catch (_) {
+      this.index = {}
+    }
+  }
+
+  static async persist(): Promise<void> {
+    try {
+      // @ts-ignore
+      await uni.setStorage({ key: this.STORAGE_KEY, data: this.index ?? {} })
+    } catch (_) {}
+  }
+
+  static async getCachedPath(url: string): Promise<string> {
+    await this.init()
+      if (this.index == null) return url
+      const index = this.index!
+      const existing = index[url] as string | null
+      if (existing != null && await this.fileExists(existing)) {
+        return existing
+      }
+      const saved = await this.downloadAndSave(url)
+        if (saved != null) {
+        this.index[url] = saved
+      await this.persist()
+      return saved
+    }
+    // fallback to remote url if save failed
+    return url
+  }
+
+  static async clear(url?: string): Promise<void> {
+    await this.init()
+      if (this.index == null) return
+          if (url != null && url != '') {
+        this.index[url] = null
+    } else {
+      this.index = {}
+    }
+    await this.persist()
+  }
+
+  private static async fileExists(filePath: string): Promise<boolean> {
+    return await new Promise<boolean>((resolve) => {
+      try {
+        const fs = uni.getFileSystemManager()
+        let settled = false
+        const finish = (value: boolean) => {
+          if (settled) {
+            return
+          }
+          settled = true
+          resolve(value)
+        }
+        fs.access({
+          path: filePath,
+          success: () => finish(true),
+          fail: () => finish(false)
+        })
+      } catch (_) {
+        resolve(false)
+      }
+    })
+  }
+  
+  private static async downloadAndSave(url: string): Promise<string | null> {
+    const dlRes = await new Promise<DownloadFileResult | null>((resolve) => {
+      try {
+        uni.downloadFile({
+          url,
+          success: (res) => {
+            const result: DownloadFileResult = {
+              statusCode: res.statusCode,
+              tempFilePath: res['tempFilePath'] as string | null,
+              tempFilePathArray: res['tempFilePathArray'] as string[] | null,
+              apFilePath: res['apFilePath'] as string | null
+            }
+            resolve(result)
+          },
+          fail: () => resolve(null)
+        })
+      } catch (_) {
+        resolve(null)
+      }
+    })
+    const statusCode = dlRes?.statusCode
+    if (dlRes == null || statusCode == null || statusCode < 200 || statusCode >= 400) {
+      return null
+    }
+    const tempFilePath = dlRes.tempFilePath ?? (dlRes.tempFilePathArray != null ? dlRes.tempFilePathArray[0] : null) ?? dlRes.apFilePath ?? null
+    if (tempFilePath == null) return null
+    const savedPath = await new Promise<string | null>((resolve) => {
+      try {
+        const fs = uni.getFileSystemManager()
+        let settled = false
+        const finish = (value: string | null) => {
+          if (settled) {
+            return
+          }
+          settled = true
+          resolve(value)
+        }
+        const options: SaveFileOptions = {
+          tempFilePath: tempFilePath,
+          success: (res) => {
+            const savedPath = res.savedFilePath
+            if (savedPath != null && savedPath.length > 0) {
+              finish(savedPath)
+              return
+            }
+            finish(null)
+          },
+          fail: () => finish(null)
+        }
+          fs.saveFile(options as SaveFileOptions)
+      } catch (_) {
+        resolve(null)
+      }
+    })
+    if (savedPath != null && savedPath.length > 0) {
+      return savedPath
+    }
+    return null
+  }
+}
+
+export default MediaCacheService