Mercurial > gemma
view pkg/controllers/shapestretches.go @ 5095:e21cbb9768a2
Prevent duplicate fairway areas
In principal, there can be only one or no fairway area at each point
on the map. Since polygons from real data will often be topologically
inexact, just disallow equal geometries. This will also help to
avoid importing duplicates with concurrent imports, once the history
of fairway dimensions will be preserved.
author | Tom Gottfried <tom@intevation.de> |
---|---|
date | Wed, 25 Mar 2020 18:10:02 +0100 |
parents | 5e38667f740c |
children | 5f47eeea988d |
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// This is Free Software under GNU Affero General Public License v >= 3.0 // without warranty, see README.md and license for details. // // SPDX-License-Identifier: AGPL-3.0-or-later // License-Filename: LICENSES/AGPL-3.0.txt // // Copyright (C) 2019 by via donau // – Österreichische Wasserstraßen-Gesellschaft mbH // Software engineering by Intevation GmbH // // Author(s): // * Sascha L. Teichmann <sascha.teichmann@intevation.de> package controllers import ( "archive/zip" "database/sql" "fmt" "io" "io/ioutil" "log" "net/http" "os" "path/filepath" "strings" "time" "github.com/gorilla/mux" "github.com/jonas-p/go-shp" "gemma.intevation.de/gemma/pkg/config" "gemma.intevation.de/gemma/pkg/middleware" "gemma.intevation.de/gemma/pkg/wkb" ) const ( selectStretchSQL = ` SELECT id, isrs_asText(lower(stretch)), isrs_asText(upper(stretch)), ST_AsBinary(area::geometry), objnam, nobjnam, date_info, source_organization FROM users.stretches WHERE staging_done AND name = $1` selectStretchCountriesSQL = ` SELECT country FROM users.stretch_countries WHERE stretch_id = $1 ORDER BY country` ) func flattenPoints(mp wkb.MultiPolygonGeom) []shp.Point { var n int for _, p := range mp { for _, r := range p { n += len(r) } } ps := make([]shp.Point, n) var i int for _, p := range mp { for _, r := range p { for _, v := range r { ps[i].X = v.X ps[i].Y = v.Y i++ } } } return ps } func asShpPolygon(mp wkb.MultiPolygonGeom) *shp.Polygon { points := flattenPoints(mp) var numParts int for _, pl := range mp { numParts += len(pl) } p := &shp.Polygon{} p.NumParts = int32(numParts) p.NumPoints = int32(len(points)) p.Parts = make([]int32, numParts) var marker int32 var i int for _, pl := range mp { for _, r := range pl { p.Parts[i] = marker i++ marker += int32(len(r)) } } p.Points = points p.Box = shp.BBoxFromPoints(points) return p } func stretchShapeDownload(rw http.ResponseWriter, req *http.Request) { vars := mux.Vars(req) name := vars["name"] conn := middleware.GetDBConn(req) ctx := req.Context() tx, err := conn.BeginTx(ctx, &sql.TxOptions{ReadOnly: true}) if err != nil { http.Error( rw, fmt.Sprintf("DB error: %v.", err), http.StatusInternalServerError) return } defer tx.Rollback() var ( id int64 lower, upper string data []byte objnam string nobjnam sql.NullString dateInfo time.Time source string ) switch err := tx.QueryRowContext(ctx, selectStretchSQL, name).Scan( &id, &lower, &upper, &data, &objnam, &nobjnam, &dateInfo, &source, ); { case err == sql.ErrNoRows: http.NotFound(rw, req) return case err != nil: http.Error( rw, fmt.Sprintf("DB error: %v.", err), http.StatusInternalServerError) return } var countries []string if err := func() error { rows, err := tx.Query(selectStretchCountriesSQL, id) if err != nil { return err } defer rows.Close() for rows.Next() { var country string if err := rows.Scan(&country); err != nil { return err } countries = append(countries, country) } return rows.Err() }(); err != nil { http.Error( rw, fmt.Sprintf("DB error: %v.", err), http.StatusInternalServerError) return } var geom wkb.MultiPolygonGeom if err := geom.FromWKB(data); err != nil { http.Error( rw, fmt.Sprintf("Decoding WKB error: %v.", err), http.StatusInternalServerError) return } tmp := config.TmpDir() dir, err := ioutil.TempDir(tmp, "stretch-download") if err != nil { http.Error( rw, fmt.Sprintf("Cannot create temp dir: %v.", err), http.StatusInternalServerError) return } defer os.RemoveAll(dir) shpDir := filepath.Join(dir, "stretch") if err := os.Mkdir(shpDir, os.ModePerm); err != nil { http.Error( rw, fmt.Sprintf("Cannot create temp dir: %v.", err), http.StatusInternalServerError) return } filename := filepath.Join(shpDir, "stretch") if err := func() error { writer, err := shp.Create(filename, shp.POLYGON) if err != nil { return err } defer writer.Close() fields := []shp.Field{ shp.StringField("NAME", 50), shp.StringField("OBJNAM", 50), shp.StringField("NOBJNAM", 50), shp.StringField("LOWER", 25), shp.StringField("UPPER", 25), shp.StringField("SOURCE", 50), shp.StringField("DATEINFO", 25), shp.StringField("COUNTRIES", 50), } writer.SetFields(fields) p := asShpPolygon(geom) writer.Write(p) write := func(field int, v interface{}) { if err == nil { err = writer.WriteAttribute(0, field, v) } } write(0, name) write(1, objnam) if nobjnam.Valid { write(2, nobjnam.String) } write(3, lower) write(4, upper) write(5, source) write(6, dateInfo.Format(time.RFC3339)) if len(countries) > 0 { write(7, strings.Join(countries, ",")) } return err }(); err != nil { http.Error( rw, fmt.Sprintf("creating shapefile failed: %v.", err), http.StatusInternalServerError) return } entries, err := func() ([]os.FileInfo, error) { f, err := os.Open(shpDir) if err != nil { return nil, err } defer f.Close() return f.Readdir(-1) }() if err != nil { http.Error( rw, fmt.Sprintf("cannot read directory: %v.", err), http.StatusInternalServerError) return } rw.Header().Set("Content-Type", "application/zip") rw.Header().Set("Content-Disposition", `attachment; filename="stretch.zip"`) zipfile := zip.NewWriter(rw) defer zipfile.Close() now := time.Now() base := filepath.Base(shpDir) for _, info := range entries { if !info.Mode().IsRegular() { continue } if err := func() error { srcFile, err := os.Open(filepath.Join(shpDir, info.Name())) if err != nil { return err } defer srcFile.Close() header := &zip.FileHeader{ Name: base + "/" + info.Name(), Method: zip.Deflate, Modified: now, } out, err := zipfile.CreateHeader(header) if err != nil { return err } _, err = io.Copy(out, srcFile) return err }(); err != nil { log.Printf("error: cannot write file: %v\n", err) return } } }