Overview

Short for Request Decoding. Missing feature of the Go standard library: decoding arbitrary HTTP requests into structs. Features:

• Transparent support for different content types / encoding formats:
  • URL query.
  • URL-encoded form.
  • Multipart form.
  • JSON.
• Transparent support for different HTTP methods:
  • Read-only -> parse only URL query.
  • Non-read-only -> parse only request body.
• Transparent support for various text-parsing interfaces.
• Support for membership testing (was X present in request?), useful for PATCH semantics.
• Tiny and dependency-free.

API docs: https://pkg.go.dev/github.com/mitranim/rd.

Example

1-call decoding. Works for any content type.

import "github.com/mitranim/rd"
import "github.com/mitranim/try"

var input struct {
  FieldOne string `json:"field_one"`
  FieldTwo int64  `json:"field_two"`
}
try.To(rd.Decode(req, &input))

Download once, decode many times. Works for any content type.

import "github.com/mitranim/rd"
import "github.com/mitranim/try"

dec := rd.TryDownload(req)

var input0 struct {
  FieldOne string `json:"field_one"`
}
try.To(dec.Decode(&input0))

var input1 struct {
  FieldTwo int64  `json:"field_two"`
}
try.To(dec.Decode(&input1))

// Membership testing.
haser := dec.Haser()
fmt.Println(haser.Has(`fieldTwo`))

Changelog

v0.3.0

Decode and Download now use the URL query when the request has no body and no content type. This library no longer checks the HTTP method of the request. Read-only methods and non-read-only methods are treated the same.

Removed Form.Download, TypeJsonUtf8, TypeFormUtf8, TypeMultiUtf8.

v0.2.3

Internal change: renamed Error.Append to Error.AppendTo for consistency with other libraries.

Minor change: added Type, TypeJsonUtf8, TypeFormUtf8, TypeMultiUtf8.

v0.2.2

Decoders now implement a new interface Setter that creates a Set of known keys.

v0.2.1

Fixed edge case bug where Form.Decode wouldn't invoke SliceParser for non-slices.

v0.2.0

Breaking revision:

• Much more flexible.
• Much faster.
• Much more test coverage.
• Renamed from reqdec to rd for brevity.
• Dependency-free.

v0.1.7

Breaking: when decoding from JSON, {"<field>": null} zeroes the matching destination field, instead of being ignored. This is an intentional deviation. The json package makes no distinction between a missing field and a field whose value is null. However, in order to support PATCH semantics, we often want to decode into non-zero output structs, updating fields that are present in the input, while ignoring fields missing from the input. Using null to zero the output is essential for this use case. If null was ignored, clients would be unable to set empty values, able only to set new non-empty values.

Breaking: when decoding from formdata, "" is treated as a "null" or "zero value" for output fields that are not slices and don't implement SliceParser. This is extremely useful for standard DOM forms.

Removed Reqdec.DecodeAt. It wasn't compatible with the new logic for struct field decoding, and supporting it separately would require code duplication.

Renamed FromQuery → FromVals.

Added FromJson.

v0.1.6

Added FromQuery and FromReqQuery.

v0.1.5

Added SliceParser for parsing non-slices from lists.

v0.1.4

Changed the license to Unlicense.

v0.1.3

When decoding into a struct where some of the fields are embedded struct pointers, those nested structs are allocated only if some of their fields are present in the request.

Also moved some reflection-related utils to a tiny dependency.

v0.1.2

First tagged release.

License

https://unlicense.org

Misc

I'm receptive to suggestions. If this library almost satisfies you but needs changes, open an issue or chat me up. Contacts: https://mitranim.com/#contacts