Method ServeRead

server/http/api_v2.go:316–373

(w http.ResponseWriter, r *http.Request)

}

func (api *APIv2) ServeRead(w http.ResponseWriter, r *http.Request) {
	format := getFormat(r, "format", hdrAccept)
	if format == nil || format.Writer == nil {
		jsonResponse(w, http.StatusBadRequest, fmt.Errorf("format is not supported for reading data"))
		return
	}
	h, err := api.handleForRequest(r)
	if err != nil {
		jsonResponse(w, http.StatusBadRequest, err)
		return
	}
	values := shape.FilterQuads(
		valuesFromString(r.FormValue("sub")),
		valuesFromString(r.FormValue("pred")),
		valuesFromString(r.FormValue("obj")),
		valuesFromString(r.FormValue("label")),
	)
	it := values.BuildIterator(h.QuadStore)
	qr := graph.NewResultReader(h.QuadStore, it)

	defer qr.Close()

	wr := writerFrom(w, r, hdrAcceptEncoding)
	defer wr.Close()

	cw := &checkWriter{w: wr}
	qwc := format.Writer(cw)
	defer qwc.Close()
	var qw quad.Writer = qwc
	if len(format.Mime) != 0 {
		w.Header().Set(hdrContentType, format.Mime[0])
	}
	if irif := r.FormValue("iri"); irif != "" {
		opts := quad.IRIOptions{
			Format: quad.IRIDefault,
		}
		switch irif {
		case "short":
			opts.Format = quad.IRIShort
		case "full":
			opts.Format = quad.IRIFull
		}
		qw = quad.IRIWriter(qw, opts)
	}
	if bw, ok := qw.(quad.BatchWriter); ok {
		_, err = quad.CopyBatch(bw, qr, api.batch)
	} else {
		_, err = quad.Copy(qw, qr)
	}
	if err != nil && !cw.written {
		jsonResponse(w, http.StatusInternalServerError, err)
		return
	} else if err != nil {
		// can do nothing here, since first byte (and header) was written
		// TODO: check if client just gone away
		clog.Errorf("read quads error: %v", err)
	}
}