frostfs-s3-gw/api/router_filter.go

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Go
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package api
import (
"fmt"
"net/http"
)
type HandlerFilters struct {
filters []Filter
defaultHandler http.Handler
}
type Filter struct {
queries []Pair
headers []Pair
h http.Handler
}
type Pair struct {
Key string
Value string
}
func NewHandlerFilter() *HandlerFilters {
return &HandlerFilters{}
}
func NewFilter() *Filter {
return &Filter{}
}
func (hf *HandlerFilters) Add(filter *Filter) *HandlerFilters {
hf.filters = append(hf.filters, *filter)
return hf
}
// HeadersMatch adds a matcher for header values.
// It accepts a sequence of key/value pairs. Values may define variables.
// Panics if number of parameters is not even.
// Supports only exact matching.
// If the value is an empty string, it will match any value if the key is set.
func (f *Filter) HeadersMatch(pairs ...string) *Filter {
length := len(pairs)
if length%2 != 0 {
panic(fmt.Errorf("filter headers: number of parameters must be multiple of 2, got %v", pairs))
}
for i := 0; i < length; i += 2 {
f.headers = append(f.headers, Pair{
Key: pairs[i],
Value: pairs[i+1],
})
}
return f
}
// Headers is similar to HeadersMatch but accept only header keys, set value to empty string internally.
func (f *Filter) Headers(headers ...string) *Filter {
for _, header := range headers {
f.headers = append(f.headers, Pair{
Key: header,
Value: "",
})
}
return f
}
func (f *Filter) Handler(handler http.HandlerFunc) *Filter {
f.h = handler
return f
}
// QueriesMatch adds a matcher for URL query values.
// It accepts a sequence of key/value pairs. Values may define variables.
// Panics if number of parameters is not even.
// Supports only exact matching.
// If the value is an empty string, it will match any value if the key is set.
func (f *Filter) QueriesMatch(pairs ...string) *Filter {
length := len(pairs)
if length%2 != 0 {
panic(fmt.Errorf("filter headers: number of parameters must be multiple of 2, got %v", pairs))
}
for i := 0; i < length; i += 2 {
f.queries = append(f.queries, Pair{
Key: pairs[i],
Value: pairs[i+1],
})
}
return f
}
// Queries is similar to QueriesMatch but accept only query keys, set value to empty string internally.
func (f *Filter) Queries(queries ...string) *Filter {
for _, query := range queries {
f.queries = append(f.queries, Pair{
Key: query,
Value: "",
})
}
return f
}
func (hf *HandlerFilters) DefaultHandler(handler http.HandlerFunc) *HandlerFilters {
hf.defaultHandler = handler
return hf
}
func (hf *HandlerFilters) ServeHTTP(w http.ResponseWriter, r *http.Request) {
if handler := hf.match(r); handler != nil {
handler.ServeHTTP(w, r)
return
}
hf.defaultHandler.ServeHTTP(w, r)
}
func (hf *HandlerFilters) match(r *http.Request) http.Handler {
LOOP:
for _, filter := range hf.filters {
for _, header := range filter.headers {
hdrVals := r.Header.Values(header.Key)
if len(hdrVals) == 0 || header.Value != "" && header.Value != hdrVals[0] {
continue LOOP
}
}
for _, query := range filter.queries {
queryVal := r.URL.Query().Get(query.Key)
if !r.URL.Query().Has(query.Key) || query.Value != "" && query.Value != queryVal {
continue LOOP
}
}
return filter.h
}
return nil
}