feat(sense): implement Control API v1 [T-011]

Sense/internal/controlapi/validation.go

@@ -0,0 +1,153 @@
+package controlapi
+
+import (
+	"bytes"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io"
+	"mime"
+	"net/http"
+	"net/url"
+	"regexp"
+	"strings"
+	"unicode/utf8"
+)
+
+const maximumRequestBody = 1 << 20
+
+var (
+	logicalIDRegex      = regexp.MustCompile(`^[A-Za-z0-9][A-Za-z0-9._:-]{0,63}$`)
+	idempotencyKeyRegex = regexp.MustCompile(`^[A-Za-z0-9._:-]{16,128}$`)
+	operationIDRegex    = regexp.MustCompile(`^op_[0-9A-HJKMNP-TV-Z]{26}$`)
+	strongETagRegex     = regexp.MustCompile(`^"[A-Za-z0-9_-]{24}"$`)
+)
+
+func readRequestBody(request *http.Request, expectedMediaType string) ([]byte, error) {
+	mediaType, _, err := mime.ParseMediaType(request.Header.Get("Content-Type"))
+	if err != nil || mediaType != expectedMediaType {
+		return nil, fmt.Errorf("Content-Type must be %s", expectedMediaType)
+	}
+	contents, err := io.ReadAll(io.LimitReader(request.Body, maximumRequestBody+1))
+	if err != nil {
+		return nil, errors.New("read request body")
+	}
+	if len(contents) == 0 || len(contents) > maximumRequestBody {
+		return nil, errors.New("request body is empty or too large")
+	}
+	if err := rejectDuplicateJSONKeys(contents); err != nil {
+		return nil, err
+	}
+	return contents, nil
+}
+
+func decodeStrictJSON(contents []byte, destination any) error {
+	decoder := json.NewDecoder(bytes.NewReader(contents))
+	decoder.DisallowUnknownFields()
+	if err := decoder.Decode(destination); err != nil {
+		return errors.New("request body does not match the API schema")
+	}
+	if decoder.Decode(&struct{}{}) != io.EOF {
+		return errors.New("request body contains trailing JSON")
+	}
+	return nil
+}
+
+func rejectTopLevelNulls(contents []byte) error {
+	var fields map[string]json.RawMessage
+	if err := json.Unmarshal(contents, &fields); err != nil || fields == nil {
+		return errors.New("request body must be a JSON object")
+	}
+	for _, value := range fields {
+		if bytes.Equal(bytes.TrimSpace(value), []byte("null")) {
+			return errors.New("request body properties cannot be null")
+		}
+	}
+	return nil
+}
+
+func rejectDuplicateJSONKeys(contents []byte) error {
+	decoder := json.NewDecoder(bytes.NewReader(contents))
+	decoder.UseNumber()
+	var visit func(int) error
+	visit = func(depth int) error {
+		if depth > 64 {
+			return errors.New("request body nesting is too deep")
+		}
+		token, err := decoder.Token()
+		if err != nil {
+			return errors.New("request body is not valid JSON")
+		}
+		delimiter, ok := token.(json.Delim)
+		if !ok {
+			return nil
+		}
+		switch delimiter {
+		case '{':
+			seen := make(map[string]struct{})
+			for decoder.More() {
+				keyToken, err := decoder.Token()
+				if err != nil {
+					return errors.New("request body is not valid JSON")
+				}
+				key, ok := keyToken.(string)
+				if !ok {
+					return errors.New("request body is not a JSON object")
+				}
+				if _, exists := seen[key]; exists {
+					return errors.New("request body contains a duplicate property")
+				}
+				seen[key] = struct{}{}
+				if err := visit(depth + 1); err != nil {
+					return err
+				}
+			}
+			end, err := decoder.Token()
+			if err != nil || end != json.Delim('}') {
+				return errors.New("request body is not valid JSON")
+			}
+		case '[':
+			for decoder.More() {
+				if err := visit(depth + 1); err != nil {
+					return err
+				}
+			}
+			end, err := decoder.Token()
+			if err != nil || end != json.Delim(']') {
+				return errors.New("request body is not valid JSON")
+			}
+		default:
+			return errors.New("request body is not valid JSON")
+		}
+		return nil
+	}
+	if err := visit(0); err != nil {
+		return err
+	}
+	if _, err := decoder.Token(); err != io.EOF {
+		return errors.New("request body contains trailing JSON")
+	}
+	return nil
+}
+
+func validLogicalID(value string) bool {
+	return logicalIDRegex.MatchString(value)
+}
+
+func validLength(value string, minimum, maximum int) bool {
+	length := utf8.RuneCountInString(value)
+	return utf8.ValidString(value) && length >= minimum && length <= maximum
+}
+
+func validateEndpoint(value string) bool {
+	if !validLength(value, 1, 2048) {
+		return false
+	}
+	parsed, err := url.Parse(value)
+	return err == nil && parsed.Scheme != "" && parsed.User == nil &&
+		!strings.ContainsAny(value, "\r\n")
+}
+
+func validStrongETag(value string) bool {
+	return strongETagRegex.MatchString(value) && value != "*" && !strings.Contains(value, ",")
+}