feat(translator): normalize and extract OpenAI file content with MIME type

- Added `NormalizeOpenAIFileData` utility to parse and validate file content, ensuring proper MIME type handling and base64 extraction.
- Refactored translation logic to use normalized file data for Gemini, Antigravity, and Interactions processors.
- Introduced comprehensive unit tests for both valid and invalid file data scenarios across all translators.

Fixed: #4416

internal/translator/antigravity/interactions/interactions_antigravity_file_data_test.go

@@ -0,0 +1,20 @@
+package interactions
+
+import (
+	"testing"
+
+	"github.com/tidwall/gjson"
+)
+
+func TestConvertInteractionsRequestToAntigravityNormalizesOpenAIFileDataURL(t *testing.T) {
+	input := []byte(`{"model":"gemini-3.5-flash","input":[{"type":"user_input","content":[{"type":"file","file":{"filename":"test.pdf","file_data":"data:application/pdf;base64,JVBERi0xLjQK"}}]}]}`)
+
+	out := ConvertInteractionsRequestToAntigravity("gemini-3.5-flash", input, false)
+	inlineData := gjson.GetBytes(out, "request.contents.0.parts.0.inlineData")
+	if got := inlineData.Get("mimeType").String(); got != "application/pdf" {
+		t.Fatalf("inlineData.mimeType = %q, want application/pdf. Output: %s", got, out)
+	}
+	if got := inlineData.Get("data").String(); got != "JVBERi0xLjQK" {
+		t.Fatalf("inlineData.data = %q, want raw base64 payload. Output: %s", got, out)
+	}
+}

internal/translator/antigravity/interactions/interactions_antigravity_request.go

@@ -5,7 +5,6 @@ import (
 	"fmt"
 	"strings"
 
-	"github.com/router-for-me/CLIProxyAPI/v7/internal/misc"
 	translatorcommon "github.com/router-for-me/CLIProxyAPI/v7/internal/translator/common"
 	"github.com/router-for-me/CLIProxyAPI/v7/internal/util"
 	"github.com/tidwall/gjson"
@@ -459,12 +458,8 @@ func appendInteractionsContentToAntigravityPart(_ []byte, content gjson.Result,
 	case "file":
 		filename := content.Get("file.filename").String()
 		fileData := content.Get("file.file_data").String()
-		ext := ""
-		if sp := strings.Split(filename, "."); len(sp) > 1 {
-			ext = sp[len(sp)-1]
-		}
-		if mimeType, ok := misc.MimeTypes[ext]; ok && fileData != "" {
-			return antigravityInlineDataPartJSON(gjson.Parse(fmt.Sprintf(`{"mime_type":%q,"data":%q}`, mimeType, fileData)))
+		if mimeType, data, ok := translatorcommon.NormalizeOpenAIFileData(filename, "", fileData); ok {
+			return antigravityInlineDataPartJSON(gjson.Parse(fmt.Sprintf(`{"mime_type":%q,"data":%q}`, mimeType, data)))
 		}
 	}
 	return nil

internal/translator/antigravity/openai/chat-completions/antigravity_openai_file_data_test.go

@@ -0,0 +1,20 @@
+package chat_completions
+
+import (
+	"testing"
+
+	"github.com/tidwall/gjson"
+)
+
+func TestConvertOpenAIRequestToAntigravityNormalizesFileDataURL(t *testing.T) {
+	input := []byte(`{"model":"gemini-2.5-pro","messages":[{"role":"user","content":[{"type":"file","file":{"filename":"test.pdf","file_data":"data:application/pdf;base64,JVBERi0xLjQK"}}]}]}`)
+
+	out := ConvertOpenAIRequestToAntigravity("gemini-2.5-pro", input, false)
+	inlineData := gjson.GetBytes(out, "request.contents.0.parts.0.inlineData")
+	if got := inlineData.Get("mimeType").String(); got != "application/pdf" {
+		t.Fatalf("inlineData.mimeType = %q, want application/pdf. Output: %s", got, out)
+	}
+	if got := inlineData.Get("data").String(); got != "JVBERi0xLjQK" {
+		t.Fatalf("inlineData.data = %q, want raw base64 payload. Output: %s", got, out)
+	}
+}

internal/translator/antigravity/openai/chat-completions/antigravity_openai_request.go

@@ -5,7 +5,6 @@ package chat_completions
 import (
 	"strings"
 
-	"github.com/router-for-me/CLIProxyAPI/v7/internal/misc"
 	translatorcommon "github.com/router-for-me/CLIProxyAPI/v7/internal/translator/common"
 	"github.com/router-for-me/CLIProxyAPI/v7/internal/translator/gemini/common"
 	"github.com/router-for-me/CLIProxyAPI/v7/internal/util"
@@ -189,14 +188,10 @@ func ConvertOpenAIRequestToAntigravity(modelName string, inputRawJSON []byte, _
 						case "file":
 							filename := item.Get("file.filename").String()
 							fileData := item.Get("file.file_data").String()
-							ext := ""
-							if pieces := strings.Split(filename, "."); len(pieces) > 1 {
-								ext = pieces[len(pieces)-1]
-							}
-							if mimeType, ok := misc.MimeTypes[ext]; ok {
-								partItems = append(partItems, antigravityOpenAIInlineDataPart(mimeType, fileData, false))
+							if mimeType, data, ok := translatorcommon.NormalizeOpenAIFileData(filename, "", fileData); ok {
+								partItems = append(partItems, antigravityOpenAIInlineDataPart(mimeType, data, false))
 							} else {
-								log.Warnf("Unknown file name extension '%s' in user message, skip", ext)
+								log.Warn("Invalid file data or unknown file name extension in user message, skip")
 							}
 						case "input_audio":
 							audioData := item.Get("input_audio.data").String()

internal/translator/common/file_data.go

@@ -0,0 +1,43 @@
+package common
+
+import (
+	"path/filepath"
+	"strings"
+
+	"github.com/router-for-me/CLIProxyAPI/v7/internal/misc"
+)
+
+// NormalizeOpenAIFileData returns the MIME type and raw base64 payload for OpenAI file content.
+func NormalizeOpenAIFileData(filename, fallbackMIMEType, fileData string) (mimeType, data string, ok bool) {
+	if fileData == "" {
+		return "", "", false
+	}
+
+	if fallbackMIMEType == "" {
+		ext := strings.ToLower(strings.TrimPrefix(filepath.Ext(filename), "."))
+		fallbackMIMEType = misc.MimeTypes[ext]
+	}
+	const dataURLPrefix = "data:"
+	if len(fileData) < len(dataURLPrefix) || !strings.EqualFold(fileData[:len(dataURLPrefix)], dataURLPrefix) {
+		if fallbackMIMEType == "" {
+			return "", "", false
+		}
+		return fallbackMIMEType, fileData, true
+	}
+
+	metadata, payload, found := strings.Cut(fileData[len(dataURLPrefix):], ",")
+	if !found || payload == "" {
+		return "", "", false
+	}
+	fields := strings.Split(metadata, ";")
+	mimeType = strings.TrimSpace(fields[0])
+	if mimeType == "" {
+		return "", "", false
+	}
+	for _, field := range fields[1:] {
+		if strings.EqualFold(strings.TrimSpace(field), "base64") {
+			return mimeType, payload, true
+		}
+	}
+	return "", "", false
+}

internal/translator/common/file_data_test.go

@@ -0,0 +1,70 @@
+package common
+
+import "testing"
+
+func TestNormalizeOpenAIFileData(t *testing.T) {
+	tests := []struct {
+		name         string
+		filename     string
+		fallbackMIME string
+		fileData     string
+		wantMIMEType string
+		wantData     string
+		wantOK       bool
+	}{
+		{
+			name:         "data URL",
+			filename:     "test.pdf",
+			fileData:     "data:application/pdf;base64,JVBERi0xLjQK",
+			wantMIMEType: "application/pdf",
+			wantData:     "JVBERi0xLjQK",
+			wantOK:       true,
+		},
+		{
+			name:         "data URL metadata and MIME override",
+			filename:     "test.txt",
+			fileData:     "data:application/pdf;charset=binary;BASE64,JVBERi0xLjQK",
+			wantMIMEType: "application/pdf",
+			wantData:     "JVBERi0xLjQK",
+			wantOK:       true,
+		},
+		{
+			name:         "case-insensitive data URL scheme",
+			filename:     "test.pdf",
+			fileData:     "DATA:application/pdf;base64,JVBERi0xLjQK",
+			wantMIMEType: "application/pdf",
+			wantData:     "JVBERi0xLjQK",
+			wantOK:       true,
+		},
+		{
+			name:         "raw base64",
+			filename:     "TEST.PDF",
+			fileData:     "JVBERi0xLjQK",
+			wantMIMEType: "application/pdf",
+			wantData:     "JVBERi0xLjQK",
+			wantOK:       true,
+		},
+		{
+			name:         "raw base64 with explicit MIME type",
+			fallbackMIME: "application/pdf",
+			fileData:     "JVBERi0xLjQK",
+			wantMIMEType: "application/pdf",
+			wantData:     "JVBERi0xLjQK",
+			wantOK:       true,
+		},
+		{name: "empty data", filename: "test.pdf"},
+		{name: "raw base64 without known extension", filename: "test", fileData: "JVBERi0xLjQK"},
+		{name: "data URL without base64 marker", filename: "test.pdf", fileData: "data:application/pdf,JVBERi0xLjQK"},
+		{name: "data URL without MIME type", filename: "test.pdf", fileData: "data:;base64,JVBERi0xLjQK"},
+		{name: "data URL without payload", filename: "test.pdf", fileData: "data:application/pdf;base64,"},
+	}
+
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			mimeType, data, ok := NormalizeOpenAIFileData(test.filename, test.fallbackMIME, test.fileData)
+			if mimeType != test.wantMIMEType || data != test.wantData || ok != test.wantOK {
+				t.Fatalf("NormalizeOpenAIFileData() = (%q, %q, %v), want (%q, %q, %v)", mimeType, data, ok, test.wantMIMEType, test.wantData, test.wantOK)
+			}
+		})
+	}
+}

internal/translator/gemini/interactions/interactions_gemini_common.go

@@ -8,7 +8,6 @@ import (
 	"strings"
 	"time"
 
-	"github.com/router-for-me/CLIProxyAPI/v7/internal/misc"
 	translatorcommon "github.com/router-for-me/CLIProxyAPI/v7/internal/translator/common"
 	"github.com/tidwall/gjson"
 	"github.com/tidwall/sjson"
@@ -878,12 +877,8 @@ func interactionsContentPartToGeminiPart(part gjson.Result, thought bool) []byte
 	case "file":
 		filename := part.Get("file.filename").String()
 		fileData := part.Get("file.file_data").String()
-		ext := ""
-		if sp := strings.Split(filename, "."); len(sp) > 1 {
-			ext = sp[len(sp)-1]
-		}
-		if mimeType, ok := misc.MimeTypes[ext]; ok && fileData != "" {
-			return geminiInlineDataPartJSON(gjson.Parse(fmt.Sprintf(`{"mime_type":%q,"data":%q}`, mimeType, fileData)))
+		if mimeType, data, ok := translatorcommon.NormalizeOpenAIFileData(filename, "", fileData); ok {
+			return geminiInlineDataPartJSON(gjson.Parse(fmt.Sprintf(`{"mime_type":%q,"data":%q}`, mimeType, data)))
 		}
 	}
 	return nil

internal/translator/gemini/interactions/interactions_gemini_file_data_test.go

@@ -0,0 +1,20 @@
+package interactions
+
+import (
+	"testing"
+
+	"github.com/tidwall/gjson"
+)
+
+func TestConvertInteractionsRequestToGeminiNormalizesOpenAIFileDataURL(t *testing.T) {
+	input := []byte(`{"model":"gemini-3.5-flash","input":[{"type":"user_input","content":[{"type":"file","file":{"filename":"test.pdf","file_data":"data:application/pdf;base64,JVBERi0xLjQK"}}]}]}`)
+
+	out := ConvertInteractionsRequestToGemini("gemini-3.5-flash", input, false)
+	inlineData := gjson.GetBytes(out, "contents.0.parts.0.inlineData")
+	if got := inlineData.Get("mimeType").String(); got != "application/pdf" {
+		t.Fatalf("inlineData.mimeType = %q, want application/pdf. Output: %s", got, out)
+	}
+	if got := inlineData.Get("data").String(); got != "JVBERi0xLjQK" {
+		t.Fatalf("inlineData.data = %q, want raw base64 payload. Output: %s", got, out)
+	}
+}

internal/translator/gemini/openai/chat-completions/gemini_openai_file_data_test.go

@@ -0,0 +1,20 @@
+package chat_completions
+
+import (
+	"testing"
+
+	"github.com/tidwall/gjson"
+)
+
+func TestConvertOpenAIRequestToGeminiNormalizesFileDataURL(t *testing.T) {
+	input := []byte(`{"model":"gemini-2.5-pro","messages":[{"role":"user","content":[{"type":"file","file":{"filename":"test.pdf","file_data":"data:application/pdf;base64,JVBERi0xLjQK"}}]}]}`)
+
+	out := ConvertOpenAIRequestToGemini("gemini-2.5-pro", input, false)
+	inlineData := gjson.GetBytes(out, "contents.0.parts.0.inlineData")
+	if got := inlineData.Get("mime_type").String(); got != "application/pdf" {
+		t.Fatalf("inlineData.mime_type = %q, want application/pdf. Output: %s", got, out)
+	}
+	if got := inlineData.Get("data").String(); got != "JVBERi0xLjQK" {
+		t.Fatalf("inlineData.data = %q, want raw base64 payload. Output: %s", got, out)
+	}
+}

internal/translator/gemini/openai/chat-completions/gemini_openai_request.go

@@ -5,7 +5,6 @@ package chat_completions
 import (
 	"strings"
 
-	"github.com/router-for-me/CLIProxyAPI/v7/internal/misc"
 	sigcompat "github.com/router-for-me/CLIProxyAPI/v7/internal/signature"
 	translatorcommon "github.com/router-for-me/CLIProxyAPI/v7/internal/translator/common"
 	"github.com/router-for-me/CLIProxyAPI/v7/internal/translator/gemini/common"
@@ -198,14 +197,10 @@ func ConvertOpenAIRequestToGemini(modelName string, inputRawJSON []byte, _ bool)
 						case "file":
 							filename := item.Get("file.filename").String()
 							fileData := item.Get("file.file_data").String()
-							ext := ""
-							if pieces := strings.Split(filename, "."); len(pieces) > 1 {
-								ext = pieces[len(pieces)-1]
-							}
-							if mimeType, ok := misc.MimeTypes[ext]; ok {
-								partItems = append(partItems, geminiInlineDataPart(mimeType, fileData, ""))
+							if mimeType, data, ok := translatorcommon.NormalizeOpenAIFileData(filename, "", fileData); ok {
+								partItems = append(partItems, geminiInlineDataPart(mimeType, data, ""))
 							} else {
-								log.Warnf("Unknown file name extension '%s' in user message, skip", ext)
+								log.Warn("Invalid file data or unknown file name extension in user message, skip")
 							}
 						case "input_audio":
 							audioData := item.Get("input_audio.data").String()

internal/translator/openai/interactions/chat-completions/openai_interactions_file_data_test.go

@@ -0,0 +1,33 @@
+package chat_completions
+
+import (
+	"testing"
+
+	"github.com/tidwall/gjson"
+)
+
+func TestConvertOpenAIRequestToInteractionsNormalizesFileDataURL(t *testing.T) {
+	input := []byte(`{"model":"gemini-3.5-flash","messages":[{"role":"user","content":[{"type":"file","file":{"filename":"test.pdf","file_data":"data:application/pdf;base64,JVBERi0xLjQK"}}]}]}`)
+
+	out := ConvertOpenAIRequestToInteractions("gemini-3.5-flash", input, false)
+	document := gjson.GetBytes(out, "input.0.content.0")
+	if got := document.Get("mime_type").String(); got != "application/pdf" {
+		t.Fatalf("document.mime_type = %q, want application/pdf. Output: %s", got, out)
+	}
+	if got := document.Get("data").String(); got != "JVBERi0xLjQK" {
+		t.Fatalf("document.data = %q, want raw base64 payload. Output: %s", got, out)
+	}
+}
+
+func TestConvertOpenAIRequestToInteractionsPreservesRawFileDataWithMIMEType(t *testing.T) {
+	input := []byte(`{"model":"gemini-3.5-flash","messages":[{"role":"user","content":[{"type":"document","mime_type":"application/pdf","data":"JVBERi0xLjQK"}]}]}`)
+
+	out := ConvertOpenAIRequestToInteractions("gemini-3.5-flash", input, false)
+	document := gjson.GetBytes(out, "input.0.content.0")
+	if got := document.Get("mime_type").String(); got != "application/pdf" {
+		t.Fatalf("document.mime_type = %q, want application/pdf. Output: %s", got, out)
+	}
+	if got := document.Get("data").String(); got != "JVBERi0xLjQK" {
+		t.Fatalf("document.data = %q, want unchanged raw base64 payload. Output: %s", got, out)
+	}
+}

internal/translator/openai/interactions/chat-completions/openai_interactions_request.go

@@ -147,17 +147,25 @@ func openAIChatContentPartToInteractions(part gjson.Result) ([]byte, bool) {
 		return out, true
 	case "file", "input_file", "document":
 		file := part.Get("file")
+		filename := firstNonEmpty(file.Get("filename").String(), part.Get("filename").String())
+		fallbackMIMEType := firstNonEmpty(file.Get("mime_type").String(), file.Get("mimeType").String(), part.Get("mime_type").String(), part.Get("mimeType").String())
+		fileData := firstNonEmpty(file.Get("file_data").String(), part.Get("file_data").String(), part.Get("data").String())
+		fileURL := firstNonEmpty(file.Get("file_url").String(), part.Get("file_url").String(), part.Get("url").String())
 		out := []byte(`{"type":"document"}`)
-		if filename := firstNonEmpty(file.Get("filename").String(), part.Get("filename").String()); filename != "" {
+		if filename != "" {
 			out, _ = sjson.SetBytes(out, "filename", filename)
 		}
-		if data := firstNonEmpty(file.Get("file_data").String(), part.Get("file_data").String(), part.Get("data").String()); data != "" {
+		hasContent := false
+		if mimeType, data, ok := translatorcommon.NormalizeOpenAIFileData(filename, fallbackMIMEType, fileData); ok {
+			out, _ = sjson.SetBytes(out, "mime_type", mimeType)
 			out, _ = sjson.SetBytes(out, "data", data)
+			hasContent = true
 		}
-		if url := firstNonEmpty(file.Get("file_url").String(), part.Get("file_url").String(), part.Get("url").String()); url != "" {
-			out, _ = sjson.SetBytes(out, "file_url", url)
+		if fileURL != "" {
+			out, _ = sjson.SetBytes(out, "file_url", fileURL)
+			hasContent = true
 		}
-		return out, true
+		return out, hasContent
 	}
 	return nil, false
 }