68 lines
1.9 KiB
Go
68 lines
1.9 KiB
Go
package internal
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import (
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"encoding/json"
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"fmt"
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"io/ioutil"
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"net/http"
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)
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func writeJSON(rw http.ResponseWriter, value interface{}, status int) {
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bytes, err := json.Marshal(value)
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if err != nil {
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panic("could not marshal value: " + err.Error())
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}
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rw.Header().Set("Content-Type", "application/json")
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rw.WriteHeader(status)
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if _, err := rw.Write(bytes); err != nil {
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panic("could not write bytes to response: " + err.Error())
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}
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}
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func writeSVG(rw http.ResponseWriter, data []byte, status int) {
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rw.Header().Set("Content-Type", "image/svg+xml")
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rw.WriteHeader(status)
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if _, err := rw.Write(data); err != nil {
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panic("could not write bytes to response: " + err.Error())
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}
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}
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func writeErr(rw http.ResponseWriter, err error, status int) {
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writeJSON(rw, map[string]interface{}{
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"error": err,
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}, status)
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}
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func GenerateHTTPHandler(generator Generator) func(rw http.ResponseWriter, r *http.Request) {
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return func(rw http.ResponseWriter, r *http.Request) {
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if r.Method != http.MethodPost {
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writeErr(rw, fmt.Errorf("expected HTTP method POST"), http.StatusBadRequest)
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return
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}
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// Get description from request body
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bytes, err := ioutil.ReadAll(r.Body)
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if err != nil {
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writeErr(rw, fmt.Errorf("could not read body: %s", err), http.StatusInternalServerError)
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return
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}
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// Create a diagram from the description
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d := NewDiagram(bytes)
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// Generate the diagram
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if err := generator.Generate(d); err != nil {
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writeErr(rw, fmt.Errorf("could not generate diagram: %s", err), http.StatusInternalServerError)
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return
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}
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// Output the diagram as an SVG.
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// We assume generate always generates an SVG at this point in time.
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diagramBytes, err := ioutil.ReadFile(d.Output)
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if err != nil {
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writeErr(rw, fmt.Errorf("could not read diagram bytes: %s", err), http.StatusInternalServerError)
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return
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}
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writeSVG(rw, diagramBytes, http.StatusOK)
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}
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}
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