mirror of
https://github.com/omniscale/magnacarto.git
synced 2025-09-28 12:33:33 +02:00
119 lines
2.6 KiB
Go
119 lines
2.6 KiB
Go
package render
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import (
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"bytes"
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"fmt"
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"net/http"
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"net/http/cgi"
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"net/url"
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"os"
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"os/exec"
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"path/filepath"
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"strings"
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)
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type MapServer struct {
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bin string
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}
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func NewMapServer() (*MapServer, error) {
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bin, err := exec.LookPath("mapserv")
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if err != nil {
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return nil, err
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}
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return &MapServer{bin: bin}, nil
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}
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func (m *MapServer) Render(mapfile string, mapReq Request) ([]byte, error) {
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if !filepath.IsAbs(mapfile) {
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if wd, err := os.Getwd(); err == nil {
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mapfile = filepath.Join(wd, mapfile)
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}
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}
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q := url.Values{}
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q.Set("REQUEST", "GetMap")
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q.Set("SERVICE", "WMS")
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q.Set("VERSION", "1.1.1")
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q.Set("STYLES", "")
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q.Set("LAYERS", "map")
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q.Set("MAP", mapfile)
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q.Set("BBOX", fmt.Sprintf("%f,%f,%f,%f", mapReq.BBOX[0], mapReq.BBOX[1], mapReq.BBOX[2], mapReq.BBOX[3]))
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q.Set("WIDTH", fmt.Sprintf("%d", mapReq.Width))
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q.Set("HEIGHT", fmt.Sprintf("%d", mapReq.Height))
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q.Set("SRS", fmt.Sprintf("EPSG:%d", mapReq.EPSGCode))
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q.Set("FORMAT", mapReq.Format)
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wd := filepath.Dir(mapfile)
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handler := cgi.Handler{
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Path: m.bin,
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Dir: wd,
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}
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w := &responseRecorder{
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Body: &bytes.Buffer{},
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}
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req, err := http.NewRequest("GET", "/?"+q.Encode(), nil)
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if err != nil {
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return nil, err
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}
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handler.ServeHTTP(w, req)
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if w.Code != 200 {
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return nil, fmt.Errorf("error while calling mapserv CGI (status %d): %v", w.Code, string(w.Body.Bytes()))
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}
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if ct := w.Header().Get("Content-type"); ct != "" && !strings.HasPrefix(ct, "image") {
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return nil, fmt.Errorf(" mapserv CGI did not return image (%v)\n%v", w.Header(), string(w.Body.Bytes()))
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}
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return w.Body.Bytes(), nil
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}
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// responseRecorder from net/http/httptest
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// copied here to work around global -httptest.server flag from httptest package
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// responseRecorder is an implementation of http.ResponseWriter that
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// records its mutations for later inspection in tests.
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type responseRecorder struct {
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Code int // the HTTP response code from WriteHeader
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HeaderMap http.Header // the HTTP response headers
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Body *bytes.Buffer // if non-nil, the bytes.Buffer to append written data to
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Flushed bool
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wroteHeader bool
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}
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func (rw *responseRecorder) 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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func (rw *responseRecorder) Write(buf []byte) (int, error) {
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if !rw.wroteHeader {
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rw.WriteHeader(200)
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}
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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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func (rw *responseRecorder) WriteHeader(code int) {
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if !rw.wroteHeader {
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rw.Code = code
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}
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rw.wroteHeader = true
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}
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func (rw *responseRecorder) Flush() {
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if !rw.wroteHeader {
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rw.WriteHeader(200)
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}
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rw.Flushed = true
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}
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