From 3d61501eb9a7b6e5b6fd444cb91af602a0e265ff Mon Sep 17 00:00:00 2001
From: Sky Johnson <skylearj@gmail.com>
Date: Thu, 6 Mar 2025 20:07:32 -0600
Subject: [PATCH] forms

---
 core/http/forms.go | 136 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 136 insertions(+)
 create mode 100644 core/http/forms.go

diff --git a/core/http/forms.go b/core/http/forms.go
new file mode 100644
index 0000000..b68d4e6
--- /dev/null
+++ b/core/http/forms.go
@@ -0,0 +1,136 @@
+package http
+
+import (
+	"errors"
+	"io"
+	"mime"
+	"net/http"
+	"net/url"
+	"strings"
+)
+
+// Maximum form parse size (16MB)
+const maxFormSize = 16 << 20
+
+// Common errors
+var (
+	ErrFormSizeTooLarge = errors.New("form size too large")
+	ErrInvalidFormType  = errors.New("invalid form content type")
+)
+
+// ParseForm parses a POST request body into a map of values
+// Supports both application/x-www-form-urlencoded and multipart/form-data content types
+func ParseForm(r *http.Request) (map[string]any, error) {
+	// Only handle POST, PUT, PATCH
+	if r.Method != http.MethodPost &&
+		r.Method != http.MethodPut &&
+		r.Method != http.MethodPatch {
+		return make(map[string]any), nil
+	}
+
+	// Check content type
+	contentType := r.Header.Get("Content-Type")
+	if contentType == "" {
+		return make(map[string]any), nil
+	}
+
+	// Parse the media type
+	mediaType, params, err := mime.ParseMediaType(contentType)
+	if err != nil {
+		return nil, ErrInvalidFormType
+	}
+
+	result := make(map[string]any)
+
+	switch {
+	case mediaType == "application/x-www-form-urlencoded":
+		// Handle URL-encoded form
+		if err := parseURLEncodedForm(r, result); err != nil {
+			return nil, err
+		}
+
+	case strings.HasPrefix(mediaType, "multipart/form-data"):
+		// Handle multipart form
+		boundary := params["boundary"]
+		if boundary == "" {
+			return nil, ErrInvalidFormType
+		}
+
+		if err := parseMultipartForm(r, boundary, result); err != nil {
+			return nil, err
+		}
+
+	default:
+		// Unrecognized content type
+		return make(map[string]any), nil
+	}
+
+	return result, nil
+}
+
+// parseURLEncodedForm handles application/x-www-form-urlencoded forms
+func parseURLEncodedForm(r *http.Request, result map[string]any) error {
+	// Enforce size limit
+	r.Body = http.MaxBytesReader(nil, r.Body, maxFormSize)
+
+	// Read the entire body
+	body, err := io.ReadAll(r.Body)
+	if err != nil {
+		if strings.Contains(err.Error(), "http: request body too large") {
+			return ErrFormSizeTooLarge
+		}
+		return err
+	}
+
+	// Parse form values
+	form, err := url.ParseQuery(string(body))
+	if err != nil {
+		return err
+	}
+
+	// Convert to map[string]any
+	for key, values := range form {
+		if len(values) == 1 {
+			// Single value
+			result[key] = values[0]
+		} else if len(values) > 1 {
+			// Multiple values
+			result[key] = values
+		}
+	}
+
+	return nil
+}
+
+// parseMultipartForm handles multipart/form-data forms
+func parseMultipartForm(r *http.Request, boundary string, result map[string]any) error {
+	// Limit the form size
+	if err := r.ParseMultipartForm(maxFormSize); err != nil {
+		if strings.Contains(err.Error(), "http: request body too large") {
+			return ErrFormSizeTooLarge
+		}
+		return err
+	}
+
+	// Process form values
+	for key, values := range r.MultipartForm.Value {
+		if len(values) == 1 {
+			// Single value
+			result[key] = values[0]
+		} else if len(values) > 1 {
+			// Multiple values
+			result[key] = values
+		}
+	}
+
+	// We don't handle file uploads here - could be extended in the future
+	// if needed to support file uploads to Lua
+
+	return nil
+}
+
+// Usage:
+// After parsing the form with ParseForm, you can add it to the context with:
+// ctx.Set("form", formData)
+//
+// This makes the form data accessible in Lua as ctx.form.field_name