Marcus Efraimsson
0390b5601e
Implements initial support for resources using v0.14.0 of SDK. Ref #21512
138 lines
3.4 KiB
Go
138 lines
3.4 KiB
Go
package resource
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import (
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"bytes"
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"net/http"
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"github.com/grafana/grafana-plugin-sdk-go/genproto/pluginv2"
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)
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// ResourceResponseWriter is an implementation of http.ResponseWriter that
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// records its mutations for later inspection in tests.
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type ResourceResponseWriter struct {
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// Code is the HTTP response code set by WriteHeader.
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//
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// Note that if a Handler never calls WriteHeader or Write,
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// this might end up being 0, rather than the implicit
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// http.StatusOK. To get the implicit value, use the Result
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// method.
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Code int
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// HeaderMap contains the headers explicitly set by the Handler.
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// It is an internal detail.
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//
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// Deprecated: HeaderMap exists for historical compatibility
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// and should not be used. To access the headers returned by a handler,
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// use the Response.Header map as returned by the Result method.
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HeaderMap http.Header
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// Body is the buffer to which the Handler's Write calls are sent.
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// If nil, the Writes are silently discarded.
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Body *bytes.Buffer
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// Flushed is whether the Handler called Flush.
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Flushed bool
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wroteHeader bool
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}
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// NewResourceResponseWriter returns an initialized ResponseWriter.
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func NewResourceResponseWriter() *ResourceResponseWriter {
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return &ResourceResponseWriter{
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HeaderMap: make(http.Header),
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Body: new(bytes.Buffer),
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Code: 200,
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}
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}
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// Header implements http.ResponseWriter. It returns the response
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// headers to mutate within a handler. To test the headers that were
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// written after a handler completes, use the Result method and see
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// the returned Response value's Header.
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func (rw *ResourceResponseWriter) Header() http.Header {
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m := rw.HeaderMap
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if m == nil {
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m = make(http.Header)
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rw.HeaderMap = m
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}
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return m
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}
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// writeHeader writes a header if it was not written yet and
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// detects Content-Type if needed.
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//
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// bytes or str are the beginning of the response body.
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// We pass both to avoid unnecessarily generate garbage
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// in rw.WriteString which was created for performance reasons.
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// Non-nil bytes win.
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func (rw *ResourceResponseWriter) writeHeader(b []byte, str string) {
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if rw.wroteHeader {
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return
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}
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if len(str) > 512 {
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str = str[:512]
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}
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m := rw.Header()
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_, hasType := m["Content-Type"]
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hasTE := m.Get("Transfer-Encoding") != ""
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if !hasType && !hasTE {
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if b == nil {
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b = []byte(str)
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}
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m.Set("Content-Type", http.DetectContentType(b))
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}
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rw.WriteHeader(200)
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}
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// Write implements http.ResponseWriter. The data in buf is written to
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// rw.Body, if not nil.
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func (rw *ResourceResponseWriter) Write(buf []byte) (int, error) {
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rw.writeHeader(buf, "")
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if rw.Body != nil {
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rw.Body.Write(buf)
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}
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return len(buf), nil
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}
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// WriteHeader implements http.ResponseWriter.
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func (rw *ResourceResponseWriter) WriteHeader(code int) {
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if rw.wroteHeader {
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return
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}
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rw.Code = code
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rw.wroteHeader = true
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if rw.HeaderMap == nil {
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rw.HeaderMap = make(http.Header)
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}
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}
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// Flush implements http.Flusher.
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func (rw *ResourceResponseWriter) Flush() {
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if !rw.wroteHeader {
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rw.WriteHeader(200)
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}
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}
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// Result returns the response generated by the handler.
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func (rw *ResourceResponseWriter) Result() *pluginv2.CallResource_Response {
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res := &pluginv2.CallResource_Response{
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Code: int32(rw.Code),
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Headers: map[string]*pluginv2.CallResource_StringList{},
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}
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if rw.Body != nil {
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res.Body = rw.Body.Bytes()
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}
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for key, values := range rw.Header().Clone() {
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res.Headers[key] = &pluginv2.CallResource_StringList{
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Values: values,
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}
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}
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return res
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}
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