Init repo

.gitignore

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+result
+vrnp
+*.swp

flake.lock

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+{
+  "nodes": {
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1720957393,
+        "narHash": "sha256-oedh2RwpjEa+TNxhg5Je9Ch6d3W1NKi7DbRO1ziHemA=",
+        "owner": "nixos",
+        "repo": "nixpkgs",
+        "rev": "693bc46d169f5af9c992095736e82c3488bf7dbb",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nixos",
+        "ref": "nixos-unstable",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "root": {
+      "inputs": {
+        "nixpkgs": "nixpkgs"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}

flake.nix

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+{
+  description = "vrnp";
+
+  inputs = {
+    nixpkgs.url = "github:nixos/nixpkgs?ref=nixos-unstable";
+  };
+
+  outputs = { self, nixpkgs }:
+  let
+    system = "x86_64-linux";
+    pkgs = nixpkgs.legacyPackages.${system};
+  in {
+    devShell.${system} = pkgs.mkShellNoCC {
+      packages = [
+        pkgs.go
+      ];
+    };
+  };
+}

go.mod

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+module pbrinkmeier/vrnp
+
+go 1.22.5

main.go

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+package main
+
+import "encoding/json"
+import "fmt"
+import "log"
+import "net/http"
+import "net/url"
+import "slices"
+import "strconv"
+
+type DMResponse struct {
+    Departures []DMDeparture `json:"departureList"`
+}
+
+type DMDeparture struct {
+    StopName string `json:"stopName"`
+    Platform string `json:"platform"`
+    Countdown string `json:"countdown"`
+    DateTime DMDateTime `json:"dateTime"`
+    RealDateTime *DMDateTime `json:"realDateTime"`
+    ServingLine DMServingLine `json:"servingLine"`
+    OnwardStopSeq []DMStop `json:"onwardStopSeq"`
+}
+
+type DMServingLine struct {
+    Symbol string `json:"symbol"`
+    Direction string `json:"direction"`
+}
+
+type DMStop struct {
+    PlaceID string `json:"placeID"`
+    Place string `json:"place"`
+    NameWO string `json:"nameWO"`
+}
+
+type DMDateTime struct {
+    Hour string `json:"hour"`
+    Minute string `json:"minute"`
+}
+
+// TODO: Use different client (with timeout)
+func FetchDepartures(stopId string) (*DMResponse, error) {
+    // Create request object
+    req, err := http.NewRequest("GET", "https://www.vrn.de/mngvrn/XML_DM_REQUEST", nil)
+    if err != nil {
+        return nil, err
+    }
+
+    // Configure our request
+    query := url.Values{}
+    query.Set("coordOutputFormat", "EPSG:4326")
+    query.Set("depType", "stopEvents")
+    query.Set("includeCompleteStopSeq", "1")
+    query.Set("limit", "10")
+    query.Set("locationServerActive", "0")
+    query.Set("mode", "direct")
+    query.Set("name_dm", stopId)
+    query.Set("outputFormat", "json")
+    query.Set("type_dm", "stop")
+    query.Set("useOnlyStops", "1")
+    query.Set("useRealtime", "1") 
+    req.URL.RawQuery = query.Encode()
+
+    // Send the request
+    res, err := http.DefaultClient.Do(req)
+    if err != nil {
+        return nil, err
+    }
+
+    defer res.Body.Close()
+    var dmResponse DMResponse
+    err = json.NewDecoder(res.Body).Decode(&dmResponse)
+    if err != nil {
+        return nil, err
+    }
+
+    return &dmResponse, nil
+}
+
+func main() {
+    http.HandleFunc("/departures", func(w http.ResponseWriter, r *http.Request) {
+        query := r.URL.Query()
+
+        if query["stop_id"] == nil || len(query["stop_id"]) < 1 {
+            http.Error(w, "Missing query parameter: stop_id", http.StatusBadRequest)
+            return
+        }
+        stopId := query["stop_id"][0]
+
+        var platform *string = nil
+        if query["platform"] != nil && len(query["platform"]) != 0 {
+            platform = &query["platform"][0]
+        }
+        
+
+        ds, err := FetchDepartures(stopId)
+        if err != nil {
+            http.Error(w, err.Error(), http.StatusInternalServerError)
+            return
+        }
+
+        for _, d := range ds.Departures {
+            if platform != nil {
+                if d.Platform != *platform {
+                    continue
+                }
+            }
+
+            direction := d.ServingLine.Direction
+            if len(d.OnwardStopSeq) != 0 {
+                last := d.OnwardStopSeq[len(d.OnwardStopSeq) - 1]
+                if slices.Contains([]string{"5", "6"}, last.PlaceID)  {
+                    direction = last.NameWO
+                }
+            }
+
+            leaving := fmt.Sprintf("%s min", d.Countdown)
+            countdown, err := strconv.Atoi(d.Countdown)
+            if err == nil {
+                if countdown == 0 {
+                    leaving = "sofort"
+                }
+                if countdown > 20 {
+                    dt := d.DateTime
+                    if d.RealDateTime != nil {
+                        dt = *d.RealDateTime
+                    }
+                    leaving = fmt.Sprintf("%02s:%02s", dt.Hour, dt.Minute)
+                }
+            }
+
+            fmt.Fprintf(w, "%2s %-22s %6s\n",
+                d.ServingLine.Symbol,
+                direction[:min(len(direction), 22)],
+                leaving,
+            )
+        }
+    })
+    log.Fatal(http.ListenAndServe(":8000", nil))
+}