oapi-codegen · cowboy-bebug · Nov 19, 2025 · Nov 19, 2025 · Nov 19, 2025 · Nov 19, 2025
@@ -0,0 +1,156 @@
+openapi: 3.0.0
+info:
+  title: Constraints Demo API
+  version: 1.0.0
+  description: Demo API to showcase constraint constants generation for both schemas and inline parameters
+
+paths:
+  /users:
+    get:
+      operationId: listUsers
+      summary: List users with pagination and filtering
+      description: Demonstrates inline parameter constraints generating constants
+      parameters:
+        - in: query
+          name: limit
+          description: Maximum number of items to return
+          schema:
+            type: integer
+            minimum: 1
+            maximum: 100
+            default: 20
+        - in: query
+          name: offset
+          description: Number of items to skip
+          schema:
+            type: integer
+            minimum: 0
+        - in: query
+          name: search
+          description: Search query string
+          schema:
+            type: string
+            minLength: 3
+            maxLength: 50
+        - in: query
+          name: minScore
+          description: Minimum score filter
+          schema:
+            type: number
+            format: float
+            minimum: 0.0
+            maximum: 100.0
+      responses:
+        "200":
+          description: List of users
+          content:
+            application/json:
+              schema:
+                type: array
+                items:
+                  $ref: "#/components/schemas/User"
+    post:
+      operationId: createUser
+      requestBody:
+        required: true
+        content:
+          application/json:
+            schema:
+              $ref: "#/components/schemas/User"
+      responses:
+        "201":
+          description: User created
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/User"
+
+  /users/{userId}:
+    get:
+      operationId: getUser
+      summary: Get a specific user by ID
+      parameters:
+        - in: path
+          name: userId
+          required: true
+          description: User ID (UUID format)
+          schema:
+            type: string
+            minLength: 36
+            maxLength: 36
+      responses:
+        "200":
+          description: User details
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/User"
+
+components:
+  schemas:
+    # These are defined as standalone types so constraints become constants
+    Username:
+      type: string
+      minLength: 3
+      maxLength: 20
+      default: "guest"
+      description: Username must be between 3 and 20 characters
+
+    Age:
+      type: integer
+      minimum: 0
+      maximum: 150
+      default: 18
+      description: User's age in years
+
+    UserScore:
+      type: number
+      format: float
+      minimum: 0.0
+      maximum: 100.0
+      default: 50.0
+      description: User score between 0 and 100
+
+    Port:
+      type: integer
+      format: int32
+      minimum: 1024
+      maximum: 65535
+      default: 8080
+      description: Preferred port number
+
+    IsActive:
+      type: boolean
+      default: true
+      description: Whether the account is active
+
+    UserTags:
+      type: array
+      items:
+        type: string
+      minItems: 1
+      maxItems: 10
+      description: User tags (1-10 items)
+
+    User:
+      type: object
+      required:
+        - username
+        - age
+      properties:
+        username:
+          $ref: "#/components/schemas/Username"
+        age:
+          $ref: "#/components/schemas/Age"
+        email:
+          type: string
+          format: email
+          maxLength: 100
+        isActive:
+          $ref: "#/components/schemas/IsActive"
+        score:
+          $ref: "#/components/schemas/UserScore"
+        port:
+          $ref: "#/components/schemas/Port"
+        tags:
+          $ref: "#/components/schemas/UserTags"
@@ -0,0 +1,8 @@
+# yaml-language-server: $schema=../../configuration-schema.json
+package: constraints
+output: gen.go
+generate:
+  models: true
+  echo-server: true
+output-options:
+  skip-prune: true
@@ -0,0 +1,178 @@
+package constraints
+
+import (
+	"fmt"
+	"net/http"
+
+	"github.com/labstack/echo/v4"
+)
+
+// Example implementation showing how to use the generated constraint constants for both schema types and inline parameters
+type Server struct{}
+
+func NewServer() *Server {
+	return &Server{}
+}
+
+// ListUsers demonstrates using constraint constants from inline parameters
+func (s *Server) ListUsers(ctx echo.Context, params ListUsersParams) error {
+	// Validate limit parameter using generated constants
+	if params.Limit != nil {
+		if *params.Limit < ListUsersLimitMinimum || *params.Limit > ListUsersLimitMaximum {
+			return echo.NewHTTPError(http.StatusBadRequest,
+				fmt.Sprintf("Limit must be between %d and %d", ListUsersLimitMinimum, ListUsersLimitMaximum))
+		}
+	} else {
+		// Use the generated default constant
+		defaultLimit := ListUsersLimitDefault
+		params.Limit = &defaultLimit
+	}
+
+	// Validate offset parameter
+	if params.Offset != nil {
+		if *params.Offset < ListUsersOffsetMinimum {
+			return echo.NewHTTPError(http.StatusBadRequest,
+				fmt.Sprintf("Offset must be at least %d", ListUsersOffsetMinimum))
+		}
+	}
+
+	// Validate search parameter length
+	if params.Search != nil {
+		searchLen := uint64(len(*params.Search))
+		if searchLen < ListUsersSearchMinLength {
+			return echo.NewHTTPError(http.StatusBadRequest,
+				fmt.Sprintf("Search must be at least %d characters", ListUsersSearchMinLength))
+		}
+		if searchLen > ListUsersSearchMaxLength {
+			return echo.NewHTTPError(http.StatusBadRequest,
+				fmt.Sprintf("Search must not exceed %d characters", ListUsersSearchMaxLength))
+		}
+	}
+
+	// Validate minScore parameter
+	if params.MinScore != nil {
+		if *params.MinScore < ListUsersMinScoreMinimum || *params.MinScore > ListUsersMinScoreMaximum {
+			return echo.NewHTTPError(http.StatusBadRequest,
+				fmt.Sprintf("MinScore must be between %.1f and %.1f", ListUsersMinScoreMinimum, ListUsersMinScoreMaximum))
+		}
+	}
+
+	fmt.Printf("Listing users with limit=%d, offset=%d\n", *params.Limit, *params.Offset)
+
+	// Return mock data (implementation not shown)
+	users := []User{}
+	return ctx.JSON(http.StatusOK, users)
+}
+
+// GetUser demonstrates using constraint constants from path parameters
+func (s *Server) GetUser(ctx echo.Context, userId string) error {
+	// Validate userId length using generated constants
+	userIdLen := uint64(len(userId))
+	if userIdLen < GetUserUserIdMinLength || userIdLen > GetUserUserIdMaxLength {
+		return echo.NewHTTPError(http.StatusBadRequest,
+			fmt.Sprintf("UserId must be exactly %d characters", GetUserUserIdMinLength))
+	}
+
+	fmt.Printf("Getting user: %s\n", userId)
+
+	// Return mock data (implementation not shown)
+	user := User{Username: UsernameDefault, Age: AgeDefault}
+	return ctx.JSON(http.StatusOK, user)
+}
+
+// CreateUser demonstrates using the generated constraint constants for validation
+func (s *Server) CreateUser(ctx echo.Context) error {
+	var user User
+	if err := ctx.Bind(&user); err != nil {
+		return echo.NewHTTPError(http.StatusBadRequest, err.Error())
+	}
+
+	// Use the generated constraint constants for validation!
+
+	// Validate age constraints
+	if user.Age < AgeMinimum || user.Age > AgeMaximum {
+		return echo.NewHTTPError(http.StatusBadRequest,
+			fmt.Sprintf("Age must be between %d and %d", AgeMinimum, AgeMaximum))
+	}
+
+	// Validate username length constraints
+	if uint64(len(user.Username)) < UsernameMinLength {
+		return echo.NewHTTPError(http.StatusBadRequest,
+			fmt.Sprintf("Username must be at least %d characters", UsernameMinLength))
+	}
+	if uint64(len(user.Username)) > UsernameMaxLength {
+		return echo.NewHTTPError(http.StatusBadRequest,
+			fmt.Sprintf("Username must not exceed %d characters", UsernameMaxLength))
+	}
+
+	// Validate port constraints (if provided)
+	if user.Port != nil {
+		if *user.Port < PortMinimum || *user.Port > PortMaximum {
+			return echo.NewHTTPError(http.StatusBadRequest,
+				fmt.Sprintf("Port must be between %d and %d", PortMinimum, PortMaximum))
+		}
+	}
+
+	// Validate user score constraints (if provided)
+	if user.Score != nil {
+		if *user.Score < UserScoreMinimum || *user.Score > UserScoreMaximum {
+			return echo.NewHTTPError(http.StatusBadRequest,
+				fmt.Sprintf("Score must be between %.1f and %.1f", UserScoreMinimum, UserScoreMaximum))
+		}
+	}
+
+	// Validate tags constraints (if provided)
+	if user.Tags != nil {
+		if uint64(len(*user.Tags)) < UserTagsMinItems {
+			return echo.NewHTTPError(http.StatusBadRequest,
+				fmt.Sprintf("Must provide at least %d tags", UserTagsMinItems))
+		}
+		if uint64(len(*user.Tags)) > UserTagsMaxItems {
+			return echo.NewHTTPError(http.StatusBadRequest,
+				fmt.Sprintf("Cannot exceed %d tags", UserTagsMaxItems))
+		}
+	}
+
+	// Use default values where appropriate
+	if user.IsActive == nil {
+		defaultActive := IsActiveDefault
+		user.IsActive = &defaultActive
+	}
+	if user.Port == nil {
+		defaultPort := PortDefault
+		user.Port = &defaultPort
+	}
+	if user.Score == nil {
+		defaultScore := UserScoreDefault
+		user.Score = &defaultScore
+	}
+
+	// Create the user (implementation not shown)
+	fmt.Printf("Creating user: %+v\n", user)
+
+	return ctx.JSON(http.StatusCreated, user)
+}
+
+// Example usage in main function
+func Example() {
+	e := echo.New()
+	server := NewServer()
+	RegisterHandlers(e, server)
+
+	fmt.Println("=== Schema Constraint Constants ===")
+	fmt.Printf("Age range: %d-%d (default: %d)\n", AgeMinimum, AgeMaximum, AgeDefault)
+	fmt.Printf("Username length: %d-%d (default: %s)\n", UsernameMinLength, UsernameMaxLength, UsernameDefault)
+	fmt.Printf("Port range: %d-%d (default: %d)\n", PortMinimum, PortMaximum, PortDefault)
+	fmt.Printf("Score range: %.1f-%.1f (default: %.1f)\n", UserScoreMinimum, UserScoreMaximum, UserScoreDefault)
+	fmt.Printf("Tags count: %d-%d\n", UserTagsMinItems, UserTagsMaxItems)
+	fmt.Printf("Is active default: %v\n", IsActiveDefault)
+
+	fmt.Println("\n=== Inline Parameter Constraint Constants ===")
+	fmt.Printf("ListUsers limit: %d-%d (default: %d)\n", ListUsersLimitMinimum, ListUsersLimitMaximum, ListUsersLimitDefault)
+	fmt.Printf("ListUsers offset: minimum %d\n", ListUsersOffsetMinimum)
+	fmt.Printf("ListUsers search length: %d-%d\n", ListUsersSearchMinLength, ListUsersSearchMaxLength)
+	fmt.Printf("ListUsers minScore: %.1f-%.1f\n", ListUsersMinScoreMinimum, ListUsersMinScoreMaximum)
+	fmt.Printf("GetUser userId length: %d-%d\n", GetUserUserIdMinLength, GetUserUserIdMaxLength)
+
+	e.Logger.Fatal(e.Start(":8080"))
+}