download BSP files from workshop

internal/core/core.go

@@ -3,22 +3,26 @@ package core
 import (
 	"archive/zip"
 	"bytes"
+	"encoding/json"
+	"fmt"
 	"io"
+	"net/http"
+	"net/url"
 	"os"
 	"path/filepath"
 
 	"github.com/galaco/bsp"
 	"github.com/pkg/errors"
 )
 
-func extractRadarImage(f *zip.File) error {
+func extractRadarImage(f *zip.File, targetDir string) error {
 	r, err := f.Open()
 	if err != nil {
 		return errors.Wrapf(err, "failed to open DDS file %q from archive", f.Name)
 	}
 	defer r.Close()
 
-	ddsFileName := filepath.Base(f.Name)
+	ddsFileName := filepath.Join(targetDir, filepath.Base(f.Name))
 	ddsF, err := os.Create(ddsFileName)
 	if err != nil {
 		return errors.Wrapf(err, "failed to create DDS file %q on disk", ddsFileName)
@@ -33,7 +37,12 @@ func extractRadarImage(f *zip.File) error {
 	return nil
 }
 
-func ExtractRadarImages(f *bsp.Bsp) error {
+func ExtractRadarImages(f *bsp.Bsp, targetDir string) error {
+	err := os.MkdirAll(targetDir, 0744)
+	if err != nil {
+		return errors.Wrapf(err, "failed to create target dir %q", targetDir)
+	}
+
 	b := f.RawLump(bsp.LumpPakfile).RawContents()
 	r := bytes.NewReader(b)
 	zipR, err := zip.NewReader(r, int64(len(b)))
@@ -43,7 +52,7 @@ func ExtractRadarImages(f *bsp.Bsp) error {
 
 	for _, pakF := range zipR.File {
 		if filepath.Ext(pakF.Name) == ".dds" {
-			err := extractRadarImage(pakF)
+			err := extractRadarImage(pakF, targetDir)
 			if err != nil {
 				return errors.Wrapf(err, "failed to extract radar image %q", pakF.Name)
 			}
@@ -52,3 +61,78 @@ func ExtractRadarImages(f *bsp.Bsp) error {
 
 	return nil
 }
+
+type GetPublishedFileDetailsResponse struct {
+	Response struct {
+		Result               int `json:"result"`
+		Resultcount          int `json:"resultcount"`
+		Publishedfiledetails []struct {
+			Publishedfileid       string `json:"publishedfileid"`
+			Result                int    `json:"result"`
+			Creator               string `json:"creator"`
+			CreatorAppID          int    `json:"creator_app_id"`
+			ConsumerAppID         int    `json:"consumer_app_id"`
+			Filename              string `json:"filename"`
+			FileSize              int    `json:"file_size"`
+			FileURL               string `json:"file_url"`
+			HcontentFile          string `json:"hcontent_file"`
+			PreviewURL            string `json:"preview_url"`
+			HcontentPreview       string `json:"hcontent_preview"`
+			Title                 string `json:"title"`
+			Description           string `json:"description"`
+			TimeCreated           int    `json:"time_created"`
+			TimeUpdated           int    `json:"time_updated"`
+			Visibility            int    `json:"visibility"`
+			Banned                int    `json:"banned"`
+			BanReason             string `json:"ban_reason"`
+			Subscriptions         int    `json:"subscriptions"`
+			Favorited             int    `json:"favorited"`
+			LifetimeSubscriptions int    `json:"lifetime_subscriptions"`
+			LifetimeFavorited     int    `json:"lifetime_favorited"`
+			Views                 int    `json:"views"`
+			Tags                  []struct {
+				Tag string `json:"tag"`
+			} `json:"tags"`
+		} `json:"publishedfiledetails"`
+	} `json:"response"`
+}
+
+func GetWorkshopFileDetails(workshopID int) (GetPublishedFileDetailsResponse, error) {
+	payload := url.Values{
+		"itemcount":           []string{"1"},
+		"publishedfileids[0]": []string{fmt.Sprint(workshopID)},
+	}
+
+	resp, err := http.PostForm("http://api.steampowered.com/ISteamRemoteStorage/GetPublishedFileDetails/v1", payload)
+	if err != nil {
+		return GetPublishedFileDetailsResponse{}, err
+	}
+
+	defer resp.Body.Close()
+
+	var respData GetPublishedFileDetailsResponse
+	dec := json.NewDecoder(resp.Body)
+	err = dec.Decode(&respData)
+	if err != nil {
+		return GetPublishedFileDetailsResponse{}, err
+	}
+
+	return respData, nil
+}
+
+func DownloadWorkshopItem(workshopID int, w io.Writer) error {
+	details, err := GetWorkshopFileDetails(workshopID)
+	if err != nil {
+		return err
+	}
+
+	resp, err := http.Get(details.Response.Publishedfiledetails[0].FileURL)
+	if err != nil {
+		return err
+	}
+	defer resp.Body.Close()
+
+	_, err = io.Copy(w, resp.Body)
+
+	return err
+}

internal/core/core_test.go

@@ -1,6 +1,12 @@
 package core_test
 
 import (
+	"archive/zip"
+	"bytes"
+	"encoding/json"
+	"fmt"
+	"os"
+	"path/filepath"
 	"testing"
 
 	"github.com/galaco/bsp"
@@ -14,6 +20,72 @@ func TestCore(t *testing.T) {
 	f, err := bsp.ReadFromFile(bspFilePath)
 	assert.NoErrorf(t, err, "failed to open BSP file %q", bspFilePath)
 
-	err = core.ExtractRadarImages(f)
+	err = core.ExtractRadarImages(f, filepath.Join(os.TempDir(), "radar-overviews"))
 	assert.NoError(t, err, "failed to extract radar images from BSP file %q", bspFilePath)
 }
+
+type crcTable struct {
+	Maps []struct {
+		Name       string `json:"map_name"`
+		Crc        uint32 `json:"map_crc"`
+		WorkshopID int    `json:"workshop_id"`
+	} `json:"maps"`
+}
+
+func TestDownload(t *testing.T) {
+	const crcTablePath = "../../test/data/crc_table.json"
+
+	f, err := os.Open(crcTablePath)
+	assert.NoErrorf(t, err, "failed to open CRC table file %q", crcTablePath)
+	defer f.Close()
+
+	var tab crcTable
+	dec := json.NewDecoder(f)
+	err = dec.Decode(&tab)
+	assert.NoErrorf(t, err, "failed to decode CRC table %q as JSON", crcTablePath)
+
+	fDownload, err := os.Create(filepath.Join(os.TempDir(), fmt.Sprintf("%s.bsp.zip", tab.Maps[0].Name)))
+	assert.NoErrorf(t, err, "failed to create target file for download %q", fDownload.Name())
+	defer f.Close()
+
+	err = core.DownloadWorkshopItem(tab.Maps[0].WorkshopID, fDownload)
+	assert.NoErrorf(t, err, "failed to download workshop item %q", tab.Maps[0].WorkshopID)
+}
+
+func TestE2E(t *testing.T) {
+	const crcTablePath = "../../test/data/crc_table.json"
+
+	f, err := os.Open(crcTablePath)
+	assert.NoErrorf(t, err, "failed to open CRC table file %q", crcTablePath)
+	defer f.Close()
+
+	var tab crcTable
+	dec := json.NewDecoder(f)
+	err = dec.Decode(&tab)
+	assert.NoErrorf(t, err, "failed to decode CRC table %q as JSON", crcTablePath)
+
+	var buf bytes.Buffer
+
+	workshopID := tab.Maps[0].WorkshopID
+	err = core.DownloadWorkshopItem(workshopID, &buf)
+	assert.NoErrorf(t, err, "failed to download workshop item %q", workshopID)
+
+	b := buf.Bytes()
+	r := bytes.NewReader(b)
+
+	zipR, err := zip.NewReader(r, int64(len(b)))
+	assert.NoErrorf(t, err, "failed to open zip reader for workshop file with ID %q", workshopID)
+
+	for _, zipF := range zipR.File {
+		if filepath.Ext(zipF.Name) == ".bsp" {
+			bspR, err := zipF.Open()
+			assert.NoErrorf(t, err, "failed to open BSP file in zip %q", zipF.Name)
+
+			bsp, err := bsp.ReadFromStream(bspR)
+			assert.NoErrorf(t, err, "failed to read BSP data from zip file stream %q", zipF.Name)
+
+			err = core.ExtractRadarImages(bsp, filepath.Join(os.TempDir(), "radar-overviews"))
+			assert.NoErrorf(t, err, "failed to extract radar images from BSP data of file %q", zipF.Name)
+		}
+	}
+}