/
mod_header.go
75 lines (57 loc) · 1.81 KB
/
mod_header.go
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package builtin
import (
"net/http"
"regexp"
"strings"
"github.com/zalando/skipper/filters"
)
type modRequestHeader struct {
headerName string
rx *regexp.Regexp
replacement string
}
// NewModRequestHeader returns a new filter Spec, whose instances execute
// regexp.ReplaceAllString on the request host. Instances expect three
// parameters: the header name, the expression to match and the replacement string.
// Name: "modRequestHeader".
func NewModRequestHeader() filters.Spec { return &modRequestHeader{} }
func (spec *modRequestHeader) Name() string {
return filters.ModRequestHeaderName
}
//lint:ignore ST1016 "spec" makes sense here and we reuse the type for the filter
func (spec *modRequestHeader) CreateFilter(config []interface{}) (filters.Filter, error) {
if len(config) != 3 {
return nil, filters.ErrInvalidFilterParameters
}
headerName, ok := config[0].(string)
if !ok {
return nil, filters.ErrInvalidFilterParameters
}
expr, ok := config[1].(string)
if !ok {
return nil, filters.ErrInvalidFilterParameters
}
replacement, ok := config[2].(string)
if !ok {
return nil, filters.ErrInvalidFilterParameters
}
rx, err := regexp.Compile(expr)
if err != nil {
return nil, err
}
return &modRequestHeader{headerName: headerName, rx: rx, replacement: replacement}, nil
}
func (f *modRequestHeader) Request(ctx filters.FilterContext) {
req := ctx.Request()
if strings.ToLower(f.headerName) == "host" {
nh := f.rx.ReplaceAllString(getRequestHost(req), f.replacement)
req.Header.Set(f.headerName, nh)
ctx.SetOutgoingHost(nh)
return
}
if _, ok := req.Header[http.CanonicalHeaderKey(f.headerName)]; !ok {
return
}
req.Header.Set(f.headerName, f.rx.ReplaceAllString(req.Header.Get(f.headerName), f.replacement))
}
func (*modRequestHeader) Response(filters.FilterContext) {}