111 lines
2.2 KiB
Go
111 lines
2.2 KiB
Go
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package gateway
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import (
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"bytes"
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"encoding/base64"
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"net/http"
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"strings"
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"github.com/aws/aws-lambda-go/events"
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)
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// ResponseWriter implements the http.ResponseWriter interface
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// in order to support the API Gateway Lambda HTTP "protocol".
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type ResponseWriter struct {
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out events.APIGatewayProxyResponse
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buf bytes.Buffer
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header http.Header
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wroteHeader bool
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}
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// NewResponse returns a new response writer to capture http output.
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func NewResponse() *ResponseWriter {
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return &ResponseWriter{}
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}
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// Header implementation.
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func (w *ResponseWriter) Header() http.Header {
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if w.header == nil {
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w.header = make(http.Header)
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}
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return w.header
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}
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// Write implementation.
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func (w *ResponseWriter) Write(b []byte) (int, error) {
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if !w.wroteHeader {
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w.WriteHeader(http.StatusOK)
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}
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// TODO: HEAD? ignore
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return w.buf.Write(b)
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}
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// WriteHeader implementation.
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func (w *ResponseWriter) WriteHeader(status int) {
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if w.wroteHeader {
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return
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}
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if w.Header().Get("Content-Type") == "" {
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w.Header().Set("Content-Type", "text/plain; charset=utf8")
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}
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w.out.StatusCode = status
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h := make(map[string]string)
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for k, v := range w.Header() {
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if len(v) > 0 {
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h[k] = v[len(v)-1]
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}
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}
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w.out.Headers = h
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w.wroteHeader = true
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}
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// End the request.
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func (w *ResponseWriter) End() events.APIGatewayProxyResponse {
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w.out.IsBase64Encoded = isBinary(w.header)
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if w.out.IsBase64Encoded {
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w.out.Body = base64.StdEncoding.EncodeToString(w.buf.Bytes())
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} else {
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w.out.Body = w.buf.String()
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}
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return w.out
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}
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// isBinary returns true if the response reprensents binary.
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func isBinary(h http.Header) bool {
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if !isTextMime(h.Get("Content-Type")) {
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return true
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}
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if h.Get("Content-Encoding") == "gzip" {
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return true
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}
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return false
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}
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// isTextMime returns true if the content type represents textual data.
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func isTextMime(kind string) bool {
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switch {
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case strings.HasSuffix(kind, "svg+xml"):
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return true
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case strings.HasPrefix(kind, "text/"):
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return true
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case strings.HasPrefix(kind, "application/") && strings.HasSuffix(kind, "json"):
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return true
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case strings.HasPrefix(kind, "application/") && strings.HasSuffix(kind, "xml"):
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return true
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default:
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return false
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}
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}
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