fix(app): support text attachments (#17335)

4 files changed, 211 insertions, 43 deletions

diff --git a/packages/app/src/components/prompt-input.tsx b/packages/app/src/components/prompt-input.tsx
index ac5beed69..5d3f5bd99 100644
--- a/packages/app/src/components/prompt-input.tsx
+++ b/packages/app/src/components/prompt-input.tsx
@@ -38,7 +38,8 @@ import { usePlatform } from "@/context/platform"
 import { useSessionLayout } from "@/pages/session/session-layout"
 import { createSessionTabs } from "@/pages/session/helpers"
 import { createTextFragment, getCursorPosition, setCursorPosition, setRangeEdge } from "./prompt-input/editor-dom"
-import { createPromptAttachments, ACCEPTED_FILE_TYPES } from "./prompt-input/attachments"
+import { createPromptAttachments } from "./prompt-input/attachments"
+import { ACCEPTED_FILE_TYPES } from "./prompt-input/files"
 import {
   canNavigateHistoryAtCursor,
   navigatePromptHistory,
@@ -1007,7 +1008,7 @@ export const PromptInput: Component<PromptInputProps> = (props) => {
     return true
   }
 
-  const { addImageAttachment, removeImageAttachment, handlePaste } = createPromptAttachments({
+  const { addAttachment, removeAttachment, handlePaste } = createPromptAttachments({
     editor: () => editorRef,
     isFocused,
     isDialogActive: () => !!dialog.active,
@@ -1247,7 +1248,7 @@ export const PromptInput: Component<PromptInputProps> = (props) => {
           onOpen={(attachment) =>
             dialog.show(() => <ImagePreview src={attachment.dataUrl} alt={attachment.filename} />)
           }
-          onRemove={removeImageAttachment}
+          onRemove={removeAttachment}
           removeLabel={language.t("prompt.attachment.remove")}
         />
         <div
@@ -1311,7 +1312,7 @@ export const PromptInput: Component<PromptInputProps> = (props) => {
               class="hidden"
               onChange={(e) => {
                 const file = e.currentTarget.files?.[0]
-                if (file) addImageAttachment(file)
+                if (file) void addAttachment(file)
                 e.currentTarget.value = ""
               }}
             />
diff --git a/packages/app/src/components/prompt-input/attachments.test.ts b/packages/app/src/components/prompt-input/attachments.test.ts
new file mode 100644
index 000000000..d8ae43d13
--- /dev/null
+++ b/packages/app/src/components/prompt-input/attachments.test.ts
@@ -0,0 +1,24 @@
+import { describe, expect, test } from "bun:test"
+import { attachmentMime } from "./files"
+
+describe("attachmentMime", () => {
+  test("keeps PDFs when the browser reports the mime", async () => {
+    const file = new File(["%PDF-1.7"], "guide.pdf", { type: "application/pdf" })
+    expect(await attachmentMime(file)).toBe("application/pdf")
+  })
+
+  test("normalizes structured text types to text/plain", async () => {
+    const file = new File(['{"ok":true}\n'], "data.json", { type: "application/json" })
+    expect(await attachmentMime(file)).toBe("text/plain")
+  })
+
+  test("accepts text files even with a misleading browser mime", async () => {
+    const file = new File(["export const x = 1\n"], "main.ts", { type: "video/mp2t" })
+    expect(await attachmentMime(file)).toBe("text/plain")
+  })
+
+  test("rejects binary files", async () => {
+    const file = new File([Uint8Array.of(0, 255, 1, 2)], "blob.bin", { type: "application/octet-stream" })
+    expect(await attachmentMime(file)).toBeUndefined()
+  })
+})
diff --git a/packages/app/src/components/prompt-input/attachments.ts b/packages/app/src/components/prompt-input/attachments.ts
index a9e4e4965..b465ea5db 100644
--- a/packages/app/src/components/prompt-input/attachments.ts
+++ b/packages/app/src/components/prompt-input/attachments.ts
@@ -4,12 +4,27 @@ import { usePrompt, type ContentPart, type ImageAttachmentPart } from "@/context
 import { useLanguage } from "@/context/language"
 import { uuid } from "@/utils/uuid"
 import { getCursorPosition } from "./editor-dom"
-
-export const ACCEPTED_IMAGE_TYPES = ["image/png", "image/jpeg", "image/gif", "image/webp"]
-export const ACCEPTED_FILE_TYPES = [...ACCEPTED_IMAGE_TYPES, "application/pdf"]
+import { attachmentMime } from "./files"
 const LARGE_PASTE_CHARS = 8000
 const LARGE_PASTE_BREAKS = 120
 
+function dataUrl(file: File, mime: string) {
+  return new Promise<string>((resolve) => {
+    const reader = new FileReader()
+    reader.addEventListener("error", () => resolve(""))
+    reader.addEventListener("load", () => {
+      const value = typeof reader.result === "string" ? reader.result : ""
+      const idx = value.indexOf(",")
+      if (idx === -1) {
+        resolve(value)
+        return
+      }
+      resolve(`data:${mime};base64,${value.slice(idx + 1)}`)
+    })
+    reader.readAsDataURL(file)
+  })
+}
+
 function largePaste(text: string) {
   if (text.length >= LARGE_PASTE_CHARS) return true
   let breaks = 0
@@ -35,28 +50,41 @@ export function createPromptAttachments(input: PromptAttachmentsInput) {
   const prompt = usePrompt()
   const language = useLanguage()
 
-  const addImageAttachment = async (file: File) => {
-    if (!ACCEPTED_FILE_TYPES.includes(file.type)) return
+  const warn = () => {
+    showToast({
+      title: language.t("prompt.toast.pasteUnsupported.title"),
+      description: language.t("prompt.toast.pasteUnsupported.description"),
+    })
+  }
 
-    const reader = new FileReader()
-    reader.onload = () => {
-      const editor = input.editor()
-      if (!editor) return
-      const dataUrl = reader.result as string
-      const attachment: ImageAttachmentPart = {
-        type: "image",
-        id: uuid(),
-        filename: file.name,
-        mime: file.type,
-        dataUrl,
-      }
-      const cursorPosition = prompt.cursor() ?? getCursorPosition(editor)
-      prompt.set([...prompt.current(), attachment], cursorPosition)
+  const add = async (file: File, toast = true) => {
+    const mime = await attachmentMime(file)
+    if (!mime) {
+      if (toast) warn()
+      return false
     }
-    reader.readAsDataURL(file)
+
+    const editor = input.editor()
+    if (!editor) return false
+
+    const url = await dataUrl(file, mime)
+    if (!url) return false
+
+    const attachment: ImageAttachmentPart = {
+      type: "image",
+      id: uuid(),
+      filename: file.name,
+      mime,
+      dataUrl: url,
+    }
+    const cursor = prompt.cursor() ?? getCursorPosition(editor)
+    prompt.set([...prompt.current(), attachment], cursor)
+    return true
   }
 
-  const removeImageAttachment = (id: string) => {
+  const addAttachment = (file: File) => add(file)
+
+  const removeAttachment = (id: string) => {
     const current = prompt.current()
     const next = current.filter((part) => part.type !== "image" || part.id !== id)
     prompt.set(next, prompt.cursor())
@@ -72,21 +100,16 @@ export function createPromptAttachments(input: PromptAttachmentsInput) {
 
     const items = Array.from(clipboardData.items)
     const fileItems = items.filter((item) => item.kind === "file")
-    const imageItems = fileItems.filter((item) => ACCEPTED_FILE_TYPES.includes(item.type))
 
-    if (imageItems.length > 0) {
-      for (const item of imageItems) {
+    if (fileItems.length > 0) {
+      let found = false
+      for (const item of fileItems) {
         const file = item.getAsFile()
-        if (file) await addImageAttachment(file)
+        if (!file) continue
+        const ok = await add(file, false)
+        if (ok) found = true
       }
-      return
-    }
-
-    if (fileItems.length > 0) {
-      showToast({
-        title: language.t("prompt.toast.pasteUnsupported.title"),
-        description: language.t("prompt.toast.pasteUnsupported.description"),
-      })
+      if (!found) warn()
       return
     }
 
@@ -96,7 +119,7 @@ export function createPromptAttachments(input: PromptAttachmentsInput) {
     if (input.readClipboardImage && !plainText) {
       const file = await input.readClipboardImage()
       if (file) {
-        await addImageAttachment(file)
+        await addAttachment(file)
         return
       }
     }
@@ -153,11 +176,12 @@ export function createPromptAttachments(input: PromptAttachmentsInput) {
     const dropped = event.dataTransfer?.files
     if (!dropped) return
 
+    let found = false
     for (const file of Array.from(dropped)) {
-      if (ACCEPTED_FILE_TYPES.includes(file.type)) {
-        await addImageAttachment(file)
-      }
+      const ok = await add(file, false)
+      if (ok) found = true
     }
+    if (!found && dropped.length > 0) warn()
   }
 
   onMount(() => {
@@ -173,8 +197,8 @@ export function createPromptAttachments(input: PromptAttachmentsInput) {
   })
 
   return {
-    addImageAttachment,
-    removeImageAttachment,
+    addAttachment,
+    removeAttachment,
     handlePaste,
   }
 }
diff --git a/packages/app/src/components/prompt-input/files.ts b/packages/app/src/components/prompt-input/files.ts
new file mode 100644
index 000000000..594991d07
--- /dev/null
+++ b/packages/app/src/components/prompt-input/files.ts
@@ -0,0 +1,119 @@
+export const ACCEPTED_IMAGE_TYPES = ["image/png", "image/jpeg", "image/gif", "image/webp"]
+
+const IMAGE_MIMES = new Set(ACCEPTED_IMAGE_TYPES)
+const IMAGE_EXTS = new Map([
+  ["gif", "image/gif"],
+  ["jpeg", "image/jpeg"],
+  ["jpg", "image/jpeg"],
+  ["png", "image/png"],
+  ["webp", "image/webp"],
+])
+const TEXT_MIMES = new Set([
+  "application/json",
+  "application/ld+json",
+  "application/toml",
+  "application/x-toml",
+  "application/x-yaml",
+  "application/xml",
+  "application/yaml",
+])
+
+export const ACCEPTED_FILE_TYPES = [
+  ...ACCEPTED_IMAGE_TYPES,
+  "application/pdf",
+  "text/*",
+  "application/json",
+  "application/ld+json",
+  "application/toml",
+  "application/x-toml",
+  "application/x-yaml",
+  "application/xml",
+  "application/yaml",
+  ".c",
+  ".cc",
+  ".cjs",
+  ".conf",
+  ".cpp",
+  ".css",
+  ".csv",
+  ".cts",
+  ".env",
+  ".go",
+  ".gql",
+  ".graphql",
+  ".h",
+  ".hh",
+  ".hpp",
+  ".htm",
+  ".html",
+  ".ini",
+  ".java",
+  ".js",
+  ".json",
+  ".jsx",
+  ".log",
+  ".md",
+  ".mdx",
+  ".mjs",
+  ".mts",
+  ".py",
+  ".rb",
+  ".rs",
+  ".sass",
+  ".scss",
+  ".sh",
+  ".sql",
+  ".toml",
+  ".ts",
+  ".tsx",
+  ".txt",
+  ".xml",
+  ".yaml",
+  ".yml",
+  ".zsh",
+]
+
+const SAMPLE = 4096
+
+function kind(type: string) {
+  return type.split(";", 1)[0]?.trim().toLowerCase() ?? ""
+}
+
+function ext(name: string) {
+  const idx = name.lastIndexOf(".")
+  if (idx === -1) return ""
+  return name.slice(idx + 1).toLowerCase()
+}
+
+function textMime(type: string) {
+  if (!type) return false
+  if (type.startsWith("text/")) return true
+  if (TEXT_MIMES.has(type)) return true
+  if (type.endsWith("+json")) return true
+  return type.endsWith("+xml")
+}
+
+function textBytes(bytes: Uint8Array) {
+  if (bytes.length === 0) return true
+  let count = 0
+  for (const byte of bytes) {
+    if (byte === 0) return false
+    if (byte < 9 || (byte > 13 && byte < 32)) count += 1
+  }
+  return count / bytes.length <= 0.3
+}
+
+export async function attachmentMime(file: File) {
+  const type = kind(file.type)
+  if (IMAGE_MIMES.has(type)) return type
+  if (type === "application/pdf") return type
+
+  const suffix = ext(file.name)
+  const fallback = IMAGE_EXTS.get(suffix) ?? (suffix === "pdf" ? "application/pdf" : undefined)
+  if ((!type || type === "application/octet-stream") && fallback) return fallback
+
+  if (textMime(type)) return "text/plain"
+  const bytes = new Uint8Array(await file.slice(0, SAMPLE).arrayBuffer())
+  if (!textBytes(bytes)) return
+  return "text/plain"
+}