Echo Route Groups: Path Prefix Issues

In this tutorial, you'll learn about Echo Route Groups: Path Prefix Issues. We cover key concepts, practical examples, and best practices.

Route groups in Echo -- Organize Echo routes with Group() for versioned APIs, shared middleware, and logical path organization.

The Problem

Echo groups are powerful but confusing when nested. Routes under a group are relative to the group prefix. Middleware added to a group only applies within that group.

Wrong

e := echo.New()
api := e.Group("/api")
api.GET("/users", getUsers)

Output:

$ curl http://localhost:8080/users
// 404 -- missing /api prefix

Right

e := echo.New()
api := e.Group("/api")
{
    api.GET("/users", getUsers)
    api.GET("/users/:id", getUser)
}
v2 := api.Group("/v2")
{
    v2.GET("/posts", getPosts)
}

Output:

$ curl http://localhost:8080/api/users
[{"id":1,"name":"Alice"}]
$ curl http://localhost:8080/api/v2/posts
[{"id":1,"title":"Hello"}]

Prevention

• Groups create path prefixes: Group("/api") + GET("/users") = /api/users
• Groups can be nested for versioning
• Middleware on a group only applies to that group
• Use groups for applying auth, rate limiting
• Groups can have their own root-level prefix

Common Mistakes with echo group

1. Using foldl instead of foldl' causing stack overflow on large lists
2. Forgetting deriving (Show, Eq) on custom data types needed for debugging
3. Placing the wildcard pattern first in case expressions, making all subsequent patterns unreachable

These mistakes appear frequently in real-world GO code. DodaTech's contributors have identified these patterns through analysis of open-source projects and production systems.

Practice Exercise

Write a pure function that safely divides two integers using Maybe, then test it with edge cases like division by zero and negative numbers.

This exercise reinforces the concepts covered in this guide. Try implementing it before checking online solutions.

FAQ

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