FEAT - OPS ATTACHMENTS: multi-format upload, stable card drop zone and text previews

plane-src/apps/api/plane/settings/common.py

@@ -461,8 +461,14 @@ ATTACHMENT_MIME_TYPES = [
     "text/css",
     "text/javascript",
     "application/json",
+    "application/x-ndjson",
+    "application/yaml",
+    "application/x-yaml",
+    "text/yaml",
+    "application/toml",
     "text/xml",
     "text/csv",
+    "text/tab-separated-values",
     "application/xml",
     # SQL
     "application/x-sql",
@@ -470,6 +476,7 @@ ATTACHMENT_MIME_TYPES = [
     "application/x-gzip",
     # Markdown
     "text/markdown",
+    "text/x-markdown",
 ]
 
 # Seed directory path

plane-src/apps/web/core/components/issues/attachment/attachment-list-item.tsx

@@ -19,11 +19,12 @@ import { EIssueServiceType } from "@plane/types";
 import type { TContextMenuItem } from "@plane/ui";
 import { ActionDropdown, EModalPosition, EModalWidth, ModalCore, Spinner } from "@plane/ui";
 import { convertBytesToSize, getFileExtension, getFileName, getFileURL, renderFormattedDate } from "@plane/utils";
-import { AlertTriangle, Box, Download, Eye, History, ImageIcon, Play, UploadCloud, X } from "lucide-react";
+import { AlertTriangle, Box, Download, Eye, FileText, History, ImageIcon, Play, UploadCloud, X } from "lucide-react";
 // components
 //
 import { ButtonAvatars } from "@/components/dropdowns/member/avatar";
 import { getFileIcon } from "@/components/icons";
+import { MarkdownRenderer } from "@/components/ui/markdown-to-component";
 import {
   buildBeamViewerUrl,
   dispatchBeamViewerOpenEvent,
@@ -57,6 +58,26 @@ type TIssueAttachmentsListItem = {
 const IMAGE_EXTENSIONS = new Set(["apng", "avif", "bmp", "gif", "jpg", "jpeg", "png", "svg", "webp"]);
 const VIDEO_EXTENSIONS = new Set(["avi", "m4v", "mov", "mp4", "mpeg", "mpg", "ogv", "webm"]);
 const PDF_EXTENSIONS = new Set(["pdf"]);
+const MARKDOWN_EXTENSIONS = new Set(["markdown", "md", "mdown", "mkd", "mkdn"]);
+const TEXT_EXTENSIONS = new Set([
+  "cfg",
+  "conf",
+  "csv",
+  "ini",
+  "json",
+  "jsonl",
+  "log",
+  "ndjson",
+  "toml",
+  "tsv",
+  "txt",
+  "xml",
+  "yaml",
+  "yml",
+]);
+const MAX_INLINE_TEXT_PREVIEW_SIZE = 8 * 1024 * 1024;
+
+type TAttachmentPreviewType = "image" | "video" | "pdf" | "markdown" | "text" | "file";
 
 const appendSearchParam = (url: string | undefined, key: string, value: string): string => {
   if (!url) return "";
@@ -94,11 +115,13 @@ const withBeamViewerSettingsSrc = (
   }
 };
 
-const getPreviewType = (extension: string) => {
+const getPreviewType = (extension: string): TAttachmentPreviewType => {
   const normalizedExtension = extension.toLowerCase();
   if (IMAGE_EXTENSIONS.has(normalizedExtension)) return "image";
   if (VIDEO_EXTENSIONS.has(normalizedExtension)) return "video";
   if (PDF_EXTENSIONS.has(normalizedExtension)) return "pdf";
+  if (MARKDOWN_EXTENSIONS.has(normalizedExtension)) return "markdown";
+  if (TEXT_EXTENSIONS.has(normalizedExtension)) return "text";
   return "file";
 };
 
@@ -170,8 +193,7 @@ export const IssueAttachmentsListItem = observer(function IssueAttachmentsListIt
         })
       : undefined) || storedModelViewerUrlWithSettings;
   const canOpenModelViewer =
-    !!beamViewer &&
+    !!beamViewer && (beamViewer.previewAvailable || beamEffectiveStatus === "ready" || !!modelViewerUrl);
-    (beamViewer.previewAvailable || beamEffectiveStatus === "ready" || !!modelViewerUrl);
   const modelDownloadUrl = beamViewer?.downloadUrl || beamViewer?.src;
   const previewDownloadUrl = modelDownloadUrl || fileURL;
   const isBeamModel = isBeamModelFile(fullFileName);
@@ -210,7 +232,8 @@ export const IssueAttachmentsListItem = observer(function IssueAttachmentsListIt
     () => mergeBeamModelVersionRecordLists(localBeamVersions, liveBeamVersions),
     [localBeamVersions, liveBeamVersions]
   );
-  const rawVersion = beamViewer?.version ?? (attachment?.attributes as { version?: number | string } | undefined)?.version;
+  const rawVersion =
+    beamViewer?.version ?? (attachment?.attributes as { version?: number | string } | undefined)?.version;
   const versionLabel =
     typeof rawVersion === "number"
       ? `v${rawVersion}`
@@ -476,15 +499,7 @@ export const IssueAttachmentsListItem = observer(function IssueAttachmentsListIt
       isMounted = false;
       if (timeoutId) window.clearTimeout(timeoutId);
     };
-  }, [
+  }, [attachmentId, attachmentService, beamViewer, issueId, projectId, storedModelViewerUrl, workspaceSlug]);
-    attachmentId,
-    attachmentService,
-    beamViewer,
-    issueId,
-    projectId,
-    storedModelViewerUrl,
-    workspaceSlug,
-  ]);
 
   if (!attachment) return <></>;
 
@@ -523,6 +538,8 @@ export const IssueAttachmentsListItem = observer(function IssueAttachmentsListIt
                   ) : (
                     <Box className="size-5 text-[rgb(var(--nodedc-accent-rgb))]" />
                   )
+                ) : previewType === "markdown" || previewType === "text" ? (
+                  <FileText className="size-5 text-[rgb(var(--nodedc-accent-rgb))]" />
                 ) : previewType === "file" ? (
                   getFileIcon(fileExtension, 18)
                 ) : (
@@ -720,6 +737,8 @@ export const IssueAttachmentsListItem = observer(function IssueAttachmentsListIt
                   ) : (
                     <Box className="size-9 text-[rgb(var(--nodedc-accent-rgb))]" />
                   )
+                ) : previewType === "markdown" || previewType === "text" ? (
+                  <FileText className="size-9 text-[rgb(var(--nodedc-accent-rgb))]" />
                 ) : previewType === "file" ? (
                   fileIcon
                 ) : (
@@ -812,7 +831,7 @@ type TAttachmentPreviewContent = {
   isBeamConversionFailed: boolean;
   modelDownloadUrl: string | undefined;
   previewDownloadUrl: string | undefined;
-  previewType: "image" | "video" | "pdf" | "file";
+  previewType: TAttachmentPreviewType;
   previewURL: string;
   setIsPreviewOpen: (isOpen: boolean) => void;
   size: number;
@@ -876,6 +895,13 @@ const AttachmentPreviewContent = (props: TAttachmentPreviewContent) => {
           </div>
         ) : previewType === "pdf" && previewURL ? (
           <IssueAttachmentPdfPreview fileURL={previewURL} />
+        ) : (previewType === "markdown" || previewType === "text") && previewURL ? (
+          <AttachmentTextPreview
+            fileName={fullFileName}
+            fileURL={previewURL}
+            isMarkdown={previewType === "markdown"}
+            size={size}
+          />
         ) : isBeamAwaitingPreview || isBeamConversionFailed ? (
           <div className="flex h-full flex-col items-center justify-center gap-4 p-8 text-center">
             <div
@@ -931,6 +957,93 @@ const AttachmentPreviewContent = (props: TAttachmentPreviewContent) => {
   );
 };
 
+type TAttachmentTextPreview = {
+  fileName: string;
+  fileURL: string;
+  isMarkdown: boolean;
+  size: number;
+};
+
+const AttachmentTextPreview = (props: TAttachmentTextPreview) => {
+  const { fileName, fileURL, isMarkdown, size } = props;
+  const [content, setContent] = useState<string | null>(null);
+  const [error, setError] = useState<string | null>(null);
+
+  useEffect(() => {
+    if (size > MAX_INLINE_TEXT_PREVIEW_SIZE) {
+      setContent(null);
+      setError(`Файл больше ${convertBytesToSize(MAX_INLINE_TEXT_PREVIEW_SIZE)}. Скачайте его для просмотра.`);
+      return;
+    }
+
+    const controller = new AbortController();
+    setContent(null);
+    setError(null);
+
+    fetch(fileURL, {
+      cache: "no-store",
+      credentials: "include",
+      signal: controller.signal,
+    })
+      .then(async (response) => {
+        if (!response.ok) throw new Error(`HTTP ${response.status}`);
+        return response.text();
+      })
+      .then((text) => setContent(text))
+      .catch((fetchError) => {
+        if (controller.signal.aborted) return;
+        console.error("Error in loading text attachment preview:", fetchError);
+        setError("Не удалось загрузить содержимое файла для предпросмотра.");
+      });
+
+    return () => controller.abort();
+  }, [fileURL, size]);
+
+  const renderedContent = useMemo(() => {
+    if (content === null || isMarkdown) return content;
+    const extension = getFileExtension(fileName).toLowerCase();
+    if (extension !== "json") return content;
+
+    try {
+      return JSON.stringify(JSON.parse(content), null, 2);
+    } catch (_error) {
+      return content;
+    }
+  }, [content, fileName, isMarkdown]);
+
+  if (error) {
+    return (
+      <div className="flex h-full items-center justify-center p-8 text-center text-14 text-secondary">{error}</div>
+    );
+  }
+
+  if (renderedContent === null) {
+    return (
+      <div className="flex h-full items-center justify-center">
+        <Spinner
+          height="34px"
+          width="34px"
+          className="fill-[rgb(var(--nodedc-accent-rgb))] text-[rgba(var(--nodedc-accent-rgb),0.18)]"
+        />
+      </div>
+    );
+  }
+
+  return (
+    <div className="vertical-scrollbar h-full overflow-auto bg-surface-1 px-6 py-5 sm:px-10 sm:py-8">
+      {isMarkdown ? (
+        <article className="nodedc-attachment-markdown-preview mx-auto max-w-4xl">
+          <MarkdownRenderer markdown={renderedContent} />
+        </article>
+      ) : (
+        <pre className="font-mono m-0 min-h-full text-13 leading-6 break-words whitespace-pre-wrap text-secondary">
+          {renderedContent}
+        </pre>
+      )}
+    </div>
+  );
+};
+
 type TBeamVersionHistoryModal = {
   currentVersionId: string | undefined;
   deletingVersionKey: string | null;

plane-src/apps/web/core/components/issues/peek-overview/view.tsx

@@ -10,14 +10,16 @@ import {
   useRef,
   useState,
   type CSSProperties,
+  type DragEvent as ReactDragEvent,
   type MouseEvent as ReactMouseEvent,
   type ReactNode,
 } from "react";
 import { observer } from "mobx-react";
 import { createPortal } from "react-dom";
-import { Download, Maximize2, Minimize2, X } from "lucide-react";
+import { Download, Maximize2, Minimize2, UploadCloud, X } from "lucide-react";
 // plane imports
 import type { EditorRefApi } from "@plane/editor";
+import { TOAST_TYPE, setToast } from "@plane/propel/toast";
 import type { TNameDescriptionLoader } from "@plane/types";
 import { EIssueServiceType } from "@plane/types";
 import { cn, convertBytesToSize } from "@plane/utils";
@@ -26,6 +28,7 @@ import { BEAM_VIEWER_OPEN_EVENT, type TBeamViewerOpenEventDetail } from "@/helpe
 import { useIssueDetail } from "@/hooks/store/use-issue-detail";
 import useKeypress from "@/hooks/use-keypress";
 import usePeekOverviewOutsideClickDetector from "@/hooks/use-peek-overview-outside-click";
+import { useFileSize } from "@/plane-web/hooks/use-file-size";
 // local imports
 import type { TIssueOperations } from "../issue-detail";
 import { IssueActivity } from "../issue-detail/issue-activity";
@@ -40,6 +43,8 @@ import { PeekOverviewProperties } from "./properties";
 const SIDE_PEEK_WIDTH_STORAGE_KEY = "nodedc:issue-peek-width";
 const BEAM_VIEWER_CLOSING_CLASS_NAME = "nodedc-beam-viewer-closing";
 
+const isFileDragEvent = (event: ReactDragEvent<HTMLElement>) => Array.from(event.dataTransfer.types).includes("Files");
+
 interface IIssueView {
   workspaceSlug: string;
   projectId: string;
@@ -96,6 +101,8 @@ export const IssueView = observer(function IssueView(props: IIssueView) {
   const [beamPeekViewer, setBeamPeekViewer] = useState<TBeamViewerOpenEventDetail | null>(null);
   const [isBeamPeekFullscreen, setIsBeamPeekFullscreen] = useState(false);
   const [isBeamPeekClosing, setIsBeamPeekClosing] = useState(false);
+  const [isCardAttachmentUploading, setIsCardAttachmentUploading] = useState(false);
+  const [isCardAttachmentDragActive, setIsCardAttachmentDragActive] = useState(false);
   const [sidePeekWidth, setSidePeekWidth] = useState<number>(() => {
     if (typeof window === "undefined") return 720;
 
@@ -114,17 +121,158 @@ export const IssueView = observer(function IssueView(props: IIssueView) {
   const initialMouseXRef = useRef<number>(0);
   const livePeekWidthRef = useRef<number>(sidePeekWidth);
   const beamCloseTimeoutRef = useRef<number | null>(null);
+  const cardAttachmentDragDepthRef = useRef(0);
   // store hooks
   const {
     setPeekIssue,
     isAnyModalOpen,
+    createAttachment,
+    fetchActivities,
+    fetchAttachments,
     issue: { getIssueById },
   } = useIssueDetail();
   const { isAnyModalOpen: isAnyEpicModalOpen } = useIssueDetail(EIssueServiceType.EPICS);
+  const { fileSizeLimitEnabled, maxFileSize } = useFileSize();
   const issue = getIssueById(issueId);
   const shouldUseInteractiveEmbeddedLayout = embedIssue && interactiveEmbeddedLayout;
   const shouldRenderPeekSurface = !embedIssue || shouldUseInteractiveEmbeddedLayout;
   const shouldAllowPeekResize = !embedIssue || shouldUseInteractiveEmbeddedLayout;
+  const isCardAttachmentDropDisabled =
+    disabled || is_archived || !!isLoading || !!isError || !issue || isCardAttachmentUploading;
+
+  const handleCardAttachmentDrop = useCallback(
+    async (acceptedFiles: File[], rejectedFileCount = 0) => {
+      if (acceptedFiles.length === 0) {
+        if (rejectedFileCount > 0) {
+          setToast({
+            type: TOAST_TYPE.ERROR,
+            title: "Файлы не прикреплены",
+            message: fileSizeLimitEnabled
+              ? `Проверьте размер файлов: максимум ${Math.round(maxFileSize / 1024 / 1024)} МБ на файл.`
+              : "Не удалось принять выбранные файлы.",
+          });
+        }
+        return;
+      }
+
+      setIsCardAttachmentUploading(true);
+      try {
+        const uploadResults = await Promise.allSettled(
+          acceptedFiles.map((file) => createAttachment(workspaceSlug, projectId, issueId, file))
+        );
+        const failedUploads = uploadResults.filter((result) => result.status === "rejected");
+
+        await Promise.allSettled([
+          fetchAttachments(workspaceSlug, projectId, issueId),
+          fetchActivities(workspaceSlug, projectId, issueId),
+        ]);
+
+        if (failedUploads.length > 0 || rejectedFileCount > 0) {
+          const failedCount = failedUploads.length + rejectedFileCount;
+          setToast({
+            type: TOAST_TYPE.ERROR,
+            title:
+              failedCount === acceptedFiles.length + rejectedFileCount ? "Файлы не прикреплены" : "Загружено не всё",
+            message: `${failedCount} ${failedCount === 1 ? "файл не удалось прикрепить" : "файла не удалось прикрепить"}.`,
+          });
+        } else {
+          setToast({
+            type: TOAST_TYPE.SUCCESS,
+            title: acceptedFiles.length === 1 ? "Файл прикреплён" : "Файлы прикреплены",
+            message:
+              acceptedFiles.length === 1
+                ? (acceptedFiles[0]?.name ?? "Вложение добавлено в карточку.")
+                : `${acceptedFiles.length} файлов добавлено в карточку.`,
+          });
+        }
+      } finally {
+        setIsCardAttachmentUploading(false);
+      }
+    },
+    [
+      createAttachment,
+      fetchActivities,
+      fetchAttachments,
+      fileSizeLimitEnabled,
+      issueId,
+      maxFileSize,
+      projectId,
+      workspaceSlug,
+    ]
+  );
+
+  const resetCardAttachmentDrag = useCallback(() => {
+    cardAttachmentDragDepthRef.current = 0;
+    setIsCardAttachmentDragActive(false);
+  }, []);
+
+  useEffect(() => {
+    window.addEventListener("dragend", resetCardAttachmentDrag, true);
+    window.addEventListener("drop", resetCardAttachmentDrag, true);
+    window.addEventListener("blur", resetCardAttachmentDrag);
+
+    return () => {
+      window.removeEventListener("dragend", resetCardAttachmentDrag, true);
+      window.removeEventListener("drop", resetCardAttachmentDrag, true);
+      window.removeEventListener("blur", resetCardAttachmentDrag);
+    };
+  }, [resetCardAttachmentDrag]);
+
+  const handleCardDragEnterCapture = useCallback(
+    (event: ReactDragEvent<HTMLDivElement>) => {
+      if (isCardAttachmentDropDisabled || !isFileDragEvent(event)) return;
+
+      event.preventDefault();
+      event.stopPropagation();
+      cardAttachmentDragDepthRef.current += 1;
+      setIsCardAttachmentDragActive(true);
+    },
+    [isCardAttachmentDropDisabled]
+  );
+
+  const handleCardDragOverCapture = useCallback(
+    (event: ReactDragEvent<HTMLDivElement>) => {
+      if (isCardAttachmentDropDisabled || !isFileDragEvent(event)) return;
+
+      event.preventDefault();
+      event.stopPropagation();
+      event.dataTransfer.dropEffect = "copy";
+      setIsCardAttachmentDragActive(true);
+    },
+    [isCardAttachmentDropDisabled]
+  );
+
+  const handleCardDragLeaveCapture = useCallback(
+    (event: ReactDragEvent<HTMLDivElement>) => {
+      if (isCardAttachmentDropDisabled || !isFileDragEvent(event)) return;
+
+      event.preventDefault();
+      event.stopPropagation();
+      cardAttachmentDragDepthRef.current = Math.max(0, cardAttachmentDragDepthRef.current - 1);
+      if (cardAttachmentDragDepthRef.current === 0) setIsCardAttachmentDragActive(false);
+    },
+    [isCardAttachmentDropDisabled]
+  );
+
+  const handleCardDropCapture = useCallback(
+    (event: ReactDragEvent<HTMLDivElement>) => {
+      if (!isFileDragEvent(event)) return;
+
+      event.preventDefault();
+      event.stopPropagation();
+      resetCardAttachmentDrag();
+      if (isCardAttachmentDropDisabled) return;
+
+      const droppedFiles = Array.from(event.dataTransfer.files);
+      const acceptedFiles = fileSizeLimitEnabled
+        ? droppedFiles.filter((file) => file.size <= maxFileSize)
+        : droppedFiles;
+      const rejectedFileCount = droppedFiles.length - acceptedFiles.length;
+
+      void handleCardAttachmentDrop(acceptedFiles, rejectedFileCount);
+    },
+    [fileSizeLimitEnabled, handleCardAttachmentDrop, isCardAttachmentDropDisabled, maxFileSize, resetCardAttachmentDrag]
+  );
   // remove peek id
   const removeRoutePeekId = () => {
     setPeekIssue(undefined);
@@ -407,7 +555,32 @@ export const IssueView = observer(function IssueView(props: IIssueView) {
   };
 
   const issuePanel = issueId ? (
-    <div ref={issuePeekOverviewRef} className={peekOverviewIssueClassName} style={issuePanelStyle}>
+    <div
+      ref={issuePeekOverviewRef}
+      className={peekOverviewIssueClassName}
+      style={issuePanelStyle}
+      data-card-attachment-drop-active={isCardAttachmentDragActive ? "true" : "false"}
+      onDragEnterCapture={handleCardDragEnterCapture}
+      onDragOverCapture={handleCardDragOverCapture}
+      onDragLeaveCapture={handleCardDragLeaveCapture}
+      onDropCapture={handleCardDropCapture}
+    >
+      {isCardAttachmentDragActive && (
+        <div className="pointer-events-none absolute inset-0 z-[96] flex items-center justify-center overflow-hidden rounded-[inherit] bg-surface-2/88 p-6 backdrop-blur-md">
+          <div className="absolute inset-3 rounded-[22px] border border-dashed border-[#303432] bg-white/[0.01]" />
+          <div className="relative flex max-w-md flex-col items-center text-center">
+            <div className="grid size-16 place-items-center rounded-3xl bg-[rgba(var(--nodedc-accent-rgb),0.14)] text-[rgb(var(--nodedc-accent-rgb))]">
+              <UploadCloud className="size-7" />
+            </div>
+            <div className="text-17 mt-5 font-semibold text-primary">Отпустите файлы, чтобы прикрепить</div>
+            <div className="mt-2 text-13 text-secondary">
+              {fileSizeLimitEnabled
+                ? `Можно несколько файлов за раз, до ${Math.round(maxFileSize / 1024 / 1024)} МБ каждый`
+                : "Можно прикрепить несколько файлов за раз"}
+            </div>
+          </div>
+        </div>
+      )}
       {shouldAllowPeekResize && peekMode === "side-peek" && (
         <div
           className="absolute top-0 left-0 z-[81] h-full w-4 -translate-x-1/2 cursor-ew-resize rounded-l-[28px] bg-transparent"

plane-src/apps/web/styles/globals.css

@@ -7523,6 +7523,81 @@
     color: var(--text-color-primary) !important;
   }
 
+  .nodedc-attachment-markdown-preview {
+    color: var(--text-color-secondary);
+    line-height: 1.7;
+  }
+
+  .nodedc-attachment-markdown-preview > * + * {
+    margin-top: 1rem;
+  }
+
+  .nodedc-attachment-markdown-preview h1,
+  .nodedc-attachment-markdown-preview h2,
+  .nodedc-attachment-markdown-preview h3,
+  .nodedc-attachment-markdown-preview h4 {
+    color: var(--text-color-primary);
+    line-height: 1.3;
+  }
+
+  .nodedc-attachment-markdown-preview h1 {
+    font-size: 1.5rem;
+  }
+
+  .nodedc-attachment-markdown-preview h2 {
+    font-size: 1.25rem;
+  }
+
+  .nodedc-attachment-markdown-preview h3,
+  .nodedc-attachment-markdown-preview h4 {
+    font-size: 1rem;
+  }
+
+  .nodedc-attachment-markdown-preview blockquote {
+    padding-left: 1rem;
+    border-left: 2px solid rgba(var(--nodedc-accent-rgb), 0.48);
+    color: var(--text-color-tertiary);
+  }
+
+  .nodedc-attachment-markdown-preview code {
+    padding: 0.12rem 0.35rem;
+    border-radius: 0.35rem;
+    background: rgba(255, 255, 255, 0.07);
+    color: var(--text-color-primary);
+    font-family: var(--font-code);
+  }
+
+  .nodedc-attachment-markdown-preview pre {
+    overflow-x: auto;
+    padding: 1rem;
+    border: 1px solid rgba(255, 255, 255, 0.07);
+    border-radius: 0.85rem;
+    background: rgba(0, 0, 0, 0.24);
+  }
+
+  .nodedc-attachment-markdown-preview pre code {
+    padding: 0;
+    background: transparent;
+  }
+
+  .nodedc-attachment-markdown-preview table {
+    display: block;
+    overflow-x: auto;
+    width: 100%;
+    border-collapse: collapse;
+  }
+
+  .nodedc-attachment-markdown-preview th,
+  .nodedc-attachment-markdown-preview td {
+    padding: 0.55rem 0.75rem;
+    border: 1px solid rgba(255, 255, 255, 0.08);
+    text-align: left;
+  }
+
+  .nodedc-attachment-markdown-preview a {
+    color: rgb(var(--nodedc-accent-rgb));
+  }
+
   .nodedc-attachments-panel[data-view-mode="list"] {
     padding-bottom: 0.75rem;
   }

plane-src/packages/services/src/file/helper.ts

@@ -10,6 +10,30 @@ import { fileTypeFromBuffer } from "file-type";
 import type { TFileMetaDataLite, TFileSignedURLResponse } from "@plane/types";
 import { DANGEROUS_EXTENSIONS } from "@plane/constants";
 
+const TEXT_MIME_TYPES_BY_EXTENSION: Readonly<Record<string, string>> = {
+  cfg: "text/plain",
+  conf: "text/plain",
+  csv: "text/csv",
+  ini: "text/plain",
+  json: "application/json",
+  jsonl: "application/x-ndjson",
+  log: "text/plain",
+  markdown: "text/markdown",
+  md: "text/markdown",
+  mdown: "text/markdown",
+  mkd: "text/markdown",
+  mkdn: "text/markdown",
+  ndjson: "application/x-ndjson",
+  toml: "application/toml",
+  tsv: "text/tab-separated-values",
+  txt: "text/plain",
+  xml: "application/xml",
+  yaml: "application/yaml",
+  yml: "application/yaml",
+};
+
+const getFileExtension = (filename: string): string => filename.split(".").pop()?.trim().toLowerCase() ?? "";
+
 /**
  * @description Filename validation - checks for double extensions and dangerous patterns
  * @param {string} filename
@@ -82,8 +106,10 @@ const detectMimeTypeFromSignature = async (file: File): Promise<string> => {
 };
 
 /**
- * @description Validate and detect the MIME type of a file using signature detection
+ * @description Validate and detect the MIME type of a file.
- * Also performs basic security checks on filename
+ * Binary signatures take precedence. Text formats are resolved from a conservative
+ * extension map because they do not have a binary signature. Browser MIME metadata
+ * and application/octet-stream provide compatibility for other safe attachments.
  * @param {File} file
  * @returns {Promise<string>} validated and detected MIME type
  */
@@ -91,7 +117,7 @@ const validateAndDetectFileType = async (file: File): Promise<string> => {
   // Basic filename validation
   const filenameError = validateFilename(file.name);
   if (filenameError) {
-    console.warn(`File validation warning: ${filenameError}`);
+    throw new Error(filenameError);
   }
 
   try {
@@ -103,8 +129,15 @@ const validateAndDetectFileType = async (file: File): Promise<string> => {
     console.warn("Error detecting file type from signature:", _error);
   }
 
-  // fallback for unknown files
+  const extensionMimeType = TEXT_MIME_TYPES_BY_EXTENSION[getFileExtension(file.name)];
-  return "";
+  if (extensionMimeType) return extensionMimeType;
+
+  const browserMimeType = file.type.split(";", 1)[0]?.trim().toLowerCase();
+  if (browserMimeType) return browserMimeType;
+
+  // Preserve generic attachment support when neither the file signature nor the
+  // browser can identify a safe filename. The API still enforces its MIME allowlist.
+  return "application/octet-stream";
 };
 
 /**