Golang - marshalling, encoding, sending responses to client applications

When using golang gin, what is the difference between c.JSON and json.NewEncoder?

In Gin, c.JSON and json.NewEncoder both facilitate sending JSON responses, but they operate at different levels of abstraction and offer distinct use cases:

1. c.JSON(statusCode int, obj interface{}) (Gin Context Method):

   1. This is a convenience method provided by the Gin framework within a gin.Context object.
   2. It handles the entire process of setting the Content-Type header to application/json, marshaling the obj (any Go data structure) into a JSON byte slice, and writing that JSON to the http.ResponseWriter with the specified statusCode.
   3. It simplifies the process of sending JSON responses, making the code cleaner and more concise for typical API endpoints.

2. json.NewEncoder(w io.Writer) (Standard Library encoding/json):

   1. This is part of Go’s standard encoding/json package.
   2. json.NewEncoder creates a new json.Encoder that writes JSON to the provided io.Writer.
   3. The Encode(v interface{}) method of the json.Encoder then takes a Go value and writes its JSON representation directly to the underlying io.Writer.
   4. It offers more fine-grained control over the encoding process and is suitable when you need to stream JSON data to a writer other than the http.ResponseWriter (e.g., a file, a network connection, or a custom buffer).
   5. It is particularly useful for handling large JSON payloads efficiently by streaming them without loading the entire data into memory at once.

Key Differences Summarized

1. Abstraction Level: c.JSON is a high-level Gin helper, while json.NewEncoder is a lower-level standard library function.
2. Convenience vs. Control: c.JSON prioritizes convenience for common API responses, while json.NewEncoder provides more control over the encoding process and target writer.
3. Target Writer: c.JSON implicitly writes to the http.ResponseWriter, whereas json.NewEncoder can write to any io.Writer.
4. Streaming: json.NewEncoder is better suited for streaming large JSON data due to its incremental writing approach, while c.JSON typically marshals the entire object into memory before writing.

What is the difference between encoding and marshalling?

1. What is the difference between json.Marshal and json.NewEncoder().Encode() in Go? https://www.reddit.com/r/golang/comments/1m4rach/what_is_the_difference_between_jsonmarshal_and/
2. In Golang, what is the difference between json encoding and marshalling https://stackoverflow.com/questions/33061117/in-golang-what-is-the-difference-between-json-encoding-and-marshalling
3. Decoding JSON using json.Unmarshal vs json.NewDecoder.Decode https://stackoverflow.com/questions/21197239/decoding-json-using-json-unmarshal-vs-json-newdecoder-decode