aicra/builder.go

130 lines
2.9 KiB
Go

package aicra
import (
"fmt"
"io"
"net/http"
"git.xdrm.io/go/aicra/api"
"git.xdrm.io/go/aicra/datatype"
"git.xdrm.io/go/aicra/internal/config"
"git.xdrm.io/go/aicra/internal/dynfunc"
)
// Builder for an aicra server
type Builder struct {
conf *config.Server
handlers []*apiHandler
middlewares []api.Middleware
}
// represents an api handler (method-pattern combination)
type apiHandler struct {
Method string
Path string
dyn *dynfunc.Handler
}
// AddType adds an available datatype to the api definition
func (b *Builder) AddType(t datatype.T) {
if b.conf == nil {
b.conf = &config.Server{}
}
if b.conf.Services != nil {
panic(errLateType)
}
b.conf.Types = append(b.conf.Types, t)
}
// With adds a middleware that will be used for each request
func (b *Builder) With(mw api.Middleware) {
if b.conf == nil {
b.conf = &config.Server{}
}
b.middlewares = append(b.middlewares, mw)
}
// Setup the builder with its api definition file
// panics if already setup
func (b *Builder) Setup(r io.Reader) error {
if b.conf == nil {
b.conf = &config.Server{}
}
if b.conf.Services != nil {
panic(errAlreadySetup)
}
return b.conf.Parse(r)
}
// Bind a dynamic handler to a REST service (method and pattern)
func (b *Builder) Bind(method, path string, fn interface{}) error {
if b.conf.Services == nil {
return errNotSetup
}
// find associated service from config
var service *config.Service
for _, s := range b.conf.Services {
if method == s.Method && path == s.Pattern {
service = s
break
}
}
if service == nil {
return fmt.Errorf("%s '%s': %w", method, path, errUnknownService)
}
var dyn, err = dynfunc.Build(fn, *service)
if err != nil {
return fmt.Errorf("%s '%s' handler: %w", method, path, err)
}
b.handlers = append(b.handlers, &apiHandler{
Path: path,
Method: method,
dyn: dyn,
})
return nil
}
// Get is equivalent to Bind(http.MethodGet)
func (b *Builder) Get(path string, fn interface{}) error {
return b.Bind(http.MethodGet, path, fn)
}
// Post is equivalent to Bind(http.MethodPost)
func (b *Builder) Post(path string, fn interface{}) error {
return b.Bind(http.MethodPost, path, fn)
}
// Put is equivalent to Bind(http.MethodPut)
func (b *Builder) Put(path string, fn interface{}) error {
return b.Bind(http.MethodPut, path, fn)
}
// Delete is equivalent to Bind(http.MethodDelete)
func (b *Builder) Delete(path string, fn interface{}) error {
return b.Bind(http.MethodDelete, path, fn)
}
// Build a fully-featured HTTP server
func (b Builder) Build() (http.Handler, error) {
for _, service := range b.conf.Services {
var isHandled bool
for _, handler := range b.handlers {
if handler.Method == service.Method && handler.Path == service.Pattern {
isHandled = true
break
}
}
if !isHandled {
return nil, fmt.Errorf("%s '%s': %w", service.Method, service.Pattern, errMissingHandler)
}
}
return Handler(b), nil
}