YARA-898

src/media-policy/media-policy.module.ts

@@ -0,0 +1,37 @@
+import { Module } from "@nestjs/common";
+import { MongooseModule } from "@nestjs/mongoose";
+
+import { ClientModule } from "src/client/client.module";
+import {
+  ClaimCase,
+  ClaimCaseSchema,
+} from "src/claim-request-management/entites/schema/claim-cases.schema";
+import {
+  BlameRequest,
+  BlameRequestSchema,
+} from "src/request-management/entities/schema/blame-cases.schema";
+
+import { MediaPolicyService } from "./media-policy.service";
+
+/**
+ * Stand-alone module so we can inject `MediaPolicyService` into both the
+ * blame and claim V2 controllers without dragging the entire
+ * `RequestManagementModule` / `ClaimRequestManagementModule` graph along
+ * (which would risk a circular dependency).
+ *
+ * The schemas are registered directly via `MongooseModule.forFeature` —
+ * Mongoose deduplicates models behind the scenes so a second registration
+ * does not create a separate model.
+ */
+@Module({
+  imports: [
+    ClientModule,
+    MongooseModule.forFeature([
+      { name: BlameRequest.name, schema: BlameRequestSchema },
+      { name: ClaimCase.name, schema: ClaimCaseSchema },
+    ]),
+  ],
+  providers: [MediaPolicyService],
+  exports: [MediaPolicyService],
+})
+export class MediaPolicyModule {}

src/media-policy/media-policy.service.ts

@@ -0,0 +1,270 @@
+import {
+  BadRequestException,
+  Injectable,
+  Logger,
+} from "@nestjs/common";
+import { InjectModel } from "@nestjs/mongoose";
+import { promises as fs } from "node:fs";
+import { Model, Types } from "mongoose";
+
+import {
+  ClientService,
+  MediaKind,
+  MediaLimits,
+} from "src/client/client.service";
+import { ClaimCase } from "src/claim-request-management/entites/schema/claim-cases.schema";
+import { BlameRequest } from "src/request-management/entities/schema/blame-cases.schema";
+
+/**
+ * Shape we expect from a multer-uploaded file. We type loosely because two
+ * different multer interceptors are in play (`FileInterceptor` and
+ * `FileFieldsInterceptor`) and we don't want to drag `Express.Multer.File`
+ * typings into a service file.
+ */
+type UploadedFileLike =
+  | (Express.Multer.File & { path?: string })
+  | undefined
+  | null;
+
+/**
+ * Resolves the relevant client for a blame/claim file and enforces the
+ * client's configured byte bounds against an uploaded file. On violation it
+ * deletes the offending file from disk (best-effort) and throws a
+ * `BadRequestException` carrying a structured payload the frontend can
+ * branch on.
+ *
+ * Client resolution:
+ *   - Blame endpoints: any party on the `BlameRequest` that has
+ *     `person.clientId` set. We pick the first one we find.
+ *   - Claim endpoints: `ClaimCase.owner.clientId`.
+ *
+ * When no clientId can be resolved (early steps, malformed ids, missing
+ * documents), the helper falls back to the system defaults declared in
+ * `DEFAULT_MEDIA_LIMITS` so the gate is still enforced.
+ */
+@Injectable()
+export class MediaPolicyService {
+  private readonly logger = new Logger(MediaPolicyService.name);
+
+  constructor(
+    @InjectModel(BlameRequest.name)
+    private readonly blameRequestModel: Model<BlameRequest>,
+    @InjectModel(ClaimCase.name)
+    private readonly claimCaseModel: Model<ClaimCase>,
+    private readonly clientService: ClientService,
+  ) {}
+
+  /**
+   * Enforce limits for a file uploaded against a `BlameRequest` (V2).
+   * Safe to call with a `null`/`undefined` file — it just no-ops, leaving
+   * "file required" errors to be raised by the existing service handlers.
+   */
+  async assertForBlame(
+    file: UploadedFileLike,
+    blameRequestId: string,
+    kind: MediaKind,
+  ): Promise<void> {
+    if (!file) return;
+    const clientId = await this.resolveBlameClientId(blameRequestId);
+    await this.assertWithClient(file, clientId, kind);
+  }
+
+  /**
+   * Enforce limits for a file uploaded against a `ClaimCase` (V2).
+   * Safe to call with a `null`/`undefined` file.
+   */
+  async assertForClaim(
+    file: UploadedFileLike,
+    claimRequestId: string,
+    kind: MediaKind,
+  ): Promise<void> {
+    if (!file) return;
+    const clientId = await this.resolveClaimClientId(claimRequestId);
+    await this.assertWithClient(file, clientId, kind);
+  }
+
+  /**
+   * Validate a bag of files (as produced by `FileFieldsInterceptor`) against
+   * the blame file's client. Each field key is mapped to a `MediaKind` via
+   * `fieldKindMap`; unmapped keys are ignored. On the first violation we
+   * delete *every* provided file (the request is being rejected anyway) and
+   * throw.
+   */
+  async assertForBlameMany<TKeys extends string>(
+    files: Partial<Record<TKeys, UploadedFileLike[] | undefined>>,
+    blameRequestId: string,
+    fieldKindMap: Record<TKeys, MediaKind | undefined>,
+  ): Promise<void> {
+    const provided = this.flattenProvidedFiles<TKeys>(files);
+    if (provided.length === 0) return;
+
+    const clientId = await this.resolveBlameClientId(blameRequestId);
+    await this.assertManyWithClient(provided, clientId, fieldKindMap);
+  }
+
+  /**
+   * Same as `assertForBlameMany` but for claim files. Use this when (and
+   * if) a multi-field claim upload endpoint is added; today's claim
+   * controllers only upload one file at a time.
+   */
+  async assertForClaimMany<TKeys extends string>(
+    files: Partial<Record<TKeys, UploadedFileLike[] | undefined>>,
+    claimRequestId: string,
+    fieldKindMap: Record<TKeys, MediaKind | undefined>,
+  ): Promise<void> {
+    const provided = this.flattenProvidedFiles<TKeys>(files);
+    if (provided.length === 0) return;
+
+    const clientId = await this.resolveClaimClientId(claimRequestId);
+    await this.assertManyWithClient(provided, clientId, fieldKindMap);
+  }
+
+  // -- internal helpers ---------------------------------------------------
+
+  private async assertWithClient(
+    file: NonNullable<UploadedFileLike>,
+    clientId: Types.ObjectId | string | null,
+    kind: MediaKind,
+  ): Promise<void> {
+    const limits = await this.clientService.getMediaLimits(clientId, kind);
+    const violation = this.checkLimits(file, limits, kind);
+    if (!violation) return;
+
+    await this.tryDelete(file?.path);
+    throw new BadRequestException(violation);
+  }
+
+  private async assertManyWithClient<TKeys extends string>(
+    provided: Array<{ field: TKeys; file: NonNullable<UploadedFileLike> }>,
+    clientId: Types.ObjectId | string | null,
+    fieldKindMap: Record<TKeys, MediaKind | undefined>,
+  ): Promise<void> {
+    const limitsCache = new Map<MediaKind, MediaLimits>();
+    const getLimits = async (kind: MediaKind) => {
+      if (!limitsCache.has(kind)) {
+        limitsCache.set(
+          kind,
+          await this.clientService.getMediaLimits(clientId, kind),
+        );
+      }
+      return limitsCache.get(kind) as MediaLimits;
+    };
+
+    for (const { field, file } of provided) {
+      const kind = fieldKindMap[field];
+      if (!kind) continue;
+      const limits = await getLimits(kind);
+      const violation = this.checkLimits(file, limits, kind, field);
+      if (!violation) continue;
+
+      // The request is being rejected — clean up all uploaded files so we
+      // don't leave orphans on disk.
+      await Promise.all(provided.map(({ file: f }) => this.tryDelete(f?.path)));
+      throw new BadRequestException(violation);
+    }
+  }
+
+  private checkLimits(
+    file: NonNullable<UploadedFileLike>,
+    { minBytes, maxBytes }: MediaLimits,
+    kind: MediaKind,
+    field?: string,
+  ): Record<string, unknown> | null {
+    const size = Number(file.size ?? 0);
+    if (!Number.isFinite(size)) {
+      return {
+        code: "MEDIA_SIZE_UNKNOWN",
+        kind,
+        ...(field ? { field } : {}),
+        message: `Could not determine the size of the uploaded ${kind} file.`,
+      };
+    }
+    if (size < minBytes) {
+      return {
+        code: "MEDIA_TOO_SMALL",
+        kind,
+        ...(field ? { field } : {}),
+        sizeBytes: size,
+        minBytes,
+        maxBytes,
+        message:
+          `Uploaded ${kind} is too small (${size} bytes). ` +
+          `Minimum allowed for this client is ${minBytes} bytes.`,
+      };
+    }
+    if (size > maxBytes) {
+      return {
+        code: "MEDIA_TOO_LARGE",
+        kind,
+        ...(field ? { field } : {}),
+        sizeBytes: size,
+        minBytes,
+        maxBytes,
+        message:
+          `Uploaded ${kind} is too large (${size} bytes). ` +
+          `Maximum allowed for this client is ${maxBytes} bytes.`,
+      };
+    }
+    return null;
+  }
+
+  private flattenProvidedFiles<TKeys extends string>(
+    files: Partial<Record<TKeys, UploadedFileLike[] | undefined>>,
+  ): Array<{ field: TKeys; file: NonNullable<UploadedFileLike> }> {
+    const out: Array<{ field: TKeys; file: NonNullable<UploadedFileLike> }> = [];
+    if (!files) return out;
+    for (const key of Object.keys(files) as TKeys[]) {
+      for (const f of files[key] || []) {
+        if (f) out.push({ field: key, file: f });
+      }
+    }
+    return out;
+  }
+
+  private async resolveBlameClientId(
+    blameRequestId: string,
+  ): Promise<Types.ObjectId | null> {
+    if (!blameRequestId || !Types.ObjectId.isValid(blameRequestId)) return null;
+
+    const blame = (await this.blameRequestModel
+      .findById(blameRequestId)
+      .select("parties")
+      .lean()
+      .exec()) as { parties?: Array<{ person?: { clientId?: Types.ObjectId } }> } | null;
+    if (!blame?.parties?.length) return null;
+
+    for (const party of blame.parties) {
+      const clientId = party?.person?.clientId;
+      if (clientId) return clientId;
+    }
+    return null;
+  }
+
+  private async resolveClaimClientId(
+    claimRequestId: string,
+  ): Promise<Types.ObjectId | null> {
+    if (!claimRequestId || !Types.ObjectId.isValid(claimRequestId)) return null;
+
+    const claim = (await this.claimCaseModel
+      .findById(claimRequestId)
+      .select("owner")
+      .lean()
+      .exec()) as { owner?: { clientId?: Types.ObjectId } } | null;
+    return claim?.owner?.clientId ?? null;
+  }
+
+  private async tryDelete(filePath?: string): Promise<void> {
+    if (!filePath) return;
+    try {
+      await fs.unlink(filePath);
+    } catch (err) {
+      // Best-effort cleanup — log and continue. The HTTP response will
+      // already carry the violation details for the client.
+      this.logger.warn(
+        `MediaPolicyService: failed to delete file at ${filePath}: ${
+          err instanceof Error ? err.message : String(err)
+        }`,
+      );
+    }
+  }
+}