sklad: move the database into its own file

2 files changed, 154 insertions, 138 deletions

diff --git a/sklad/db.go b/sklad/db.go
new file mode 100644
index 0000000..c036cb8
--- /dev/null
+++ b/sklad/db.go
@@ -0,0 +1,149 @@
+package main
+
+import (
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io"
+	"os"
+)
+
+type Series struct {
+	Prefix      string // PK: prefix
+	Description string // what kind of containers this is for
+}
+
+type Container struct {
+	Series      string      // PK: what series does this belong to
+	Number      uint        // PK: order within the series
+	Parent      ContainerId // the container we're in, if any, otherwise ""
+	Description string      // description and/or contents of this container
+}
+
+type ContainerId string
+
+func (c *Container) Id() ContainerId {
+	return ContainerId(fmt.Sprintf("%s%s%d", db.Prefix, c.Series, c.Number))
+}
+
+type Database struct {
+	Password   string       // password for web users
+	Prefix     string       // prefix for all container IDs
+	Series     []*Series    // all known series
+	Containers []*Container // all known containers
+}
+
+var (
+	dbPath string
+	db     Database
+	dbLast Database
+	dbLog  io.Writer
+
+	indexSeries    = map[string]*Series{}
+	indexContainer = map[ContainerId]*Container{}
+	indexChildren  = map[ContainerId][]*Container{}
+)
+
+// TODO: Some functions to add, remove and change things in the database.
+// Indexes must be kept valid, just like any invariants.
+
+// TODO: A function for fulltext search in series (1. Prefix, 2. Description).
+
+// TODO: A function for fulltext search in containers (1. Id, 2. Description).
+
+func dbCommit() error {
+	// Back up the current database contents.
+	e := json.NewEncoder(dbLog)
+	e.SetIndent("", "  ")
+	if err := e.Encode(&dbLast); err != nil {
+		return err
+	}
+
+	// Atomically replace the current database file.
+	tempPath := dbPath + ".new"
+	temp, err := os.OpenFile(tempPath, os.O_WRONLY|os.O_CREATE, 0644)
+	if err != nil {
+		return err
+	}
+	defer temp.Close()
+
+	e = json.NewEncoder(temp)
+	e.SetIndent("", "  ")
+	if err := e.Encode(&db); err != nil {
+		return err
+	}
+
+	if err := os.Rename(tempPath, dbPath); err != nil {
+		return err
+	}
+
+	dbLast = db
+	return nil
+}
+
+// loadDatabase loads the database from a simple JSON file. We do not use
+// any SQL stuff or even external KV storage because there is no real need
+// for our trivial use case, with our general amount of data.
+func loadDatabase() error {
+	dbFile, err := os.Open(dbPath)
+	if err != nil {
+		return err
+	}
+	if err := json.NewDecoder(dbFile).Decode(&db); err != nil {
+		return err
+	}
+
+	// Further validate the database.
+	if db.Prefix == "" {
+		return errors.New("misconfigured prefix")
+	}
+
+	// Construct indexes for primary keys, validate against duplicates.
+	for _, pv := range db.Series {
+		if _, ok := indexSeries[pv.Prefix]; ok {
+			return fmt.Errorf("duplicate series: %s", pv.Prefix)
+		}
+		indexSeries[pv.Prefix] = pv
+	}
+	for _, pv := range db.Containers {
+		id := pv.Id()
+		if _, ok := indexContainer[id]; ok {
+			return fmt.Errorf("duplicate container: %s", id)
+		}
+		indexContainer[id] = pv
+	}
+
+	// Construct an index that goes from parent containers to their children.
+	for _, pv := range db.Containers {
+		if pv.Parent == "" {
+			continue
+		}
+		if _, ok := indexContainer[pv.Parent]; !ok {
+			return fmt.Errorf("container %s has a nonexistent parent %s",
+				pv.Id(), pv.Parent)
+		}
+		indexChildren[pv.Parent] = append(indexChildren[pv.Parent], pv)
+	}
+
+	// Validate that no container is a parent of itself on any level.
+	for _, pv := range db.Containers {
+		parents := map[ContainerId]bool{pv.Id(): true}
+		for pv.Parent != "" {
+			if parents[pv.Parent] {
+				return fmt.Errorf("%s contains itself", pv.Parent)
+			}
+			parents[pv.Parent] = true
+			pv = indexContainer[pv.Parent]
+		}
+	}
+
+	// Open database log file for appending.
+	if dbLog, err = os.OpenFile(dbPath+".log",
+		os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0644); err != nil {
+		return err
+	}
+
+	// Remember the current state of the database.
+	dbLast = db
+	return nil
+}
diff --git a/sklad/main.go b/sklad/main.go
index 28fb258..c1eaa99 100644
--- a/sklad/main.go
+++ b/sklad/main.go
@@ -1,155 +1,19 @@
 package main
 
 import (
-	"encoding/json"
-	"errors"
-	"fmt"
 	"html/template"
-	"io"
 	"log"
 	"net/http"
 	"os"
 )
 
-type Series struct {
-	Prefix      string // PK: prefix
-	Description string // what kind of containers this is for
-}
-
-type Container struct {
-	Series      string      // PK: what series does this belong to
-	Number      uint        // PK: order within the series
-	Parent      ContainerId // the container we're in, if any, otherwise ""
-	Description string      // description and/or contents of this container
-}
-
-type ContainerId string
-
-func (c *Container) Id() ContainerId {
-	return ContainerId(fmt.Sprintf("%s%s%d", db.Prefix, c.Series, c.Number))
-}
-
-type Database struct {
-	Password   string       // password for web users
-	Prefix     string       // prefix for all container IDs
-	Series     []*Series    // all known series
-	Containers []*Container // all known containers
-}
-
 var (
 	templates *template.Template
-	// TODO: Some kind of session storage, somewhere.
-
-	dbPath string
-	db     Database
-	dbLast Database
-	dbLog  io.Writer
 
-	indexSeries    = map[string]*Series{}
-	indexContainer = map[ContainerId]*Container{}
-	indexChildren  = map[ContainerId][]*Container{}
+	// session storage: UUID -> net.SplitHostPort(http.Server.RemoteAddr)[0]
+	sessions = map[string]string{}
 )
 
-// TODO: Some functions to add, remove and change things in the database.
-// Indexes must be kept valid, just like any invariants.
-
-func dbCommit() error {
-	// Back up the current database contents.
-	e := json.NewEncoder(dbLog)
-	e.SetIndent("", "  ")
-	if err := e.Encode(&dbLast); err != nil {
-		return err
-	}
-
-	// Atomically replace the current database file.
-	tempPath := dbPath + ".new"
-	temp, err := os.OpenFile(tempPath, os.O_WRONLY|os.O_CREATE, 0644)
-	if err != nil {
-		return err
-	}
-	defer temp.Close()
-
-	e = json.NewEncoder(temp)
-	e.SetIndent("", "  ")
-	if err := e.Encode(&db); err != nil {
-		return err
-	}
-
-	if err := os.Rename(tempPath, dbPath); err != nil {
-		return err
-	}
-
-	dbLast = db
-	return nil
-}
-
-// loadDatabase loads the database from a simple JSON file. We do not use
-// any SQL stuff or even external KV storage because there is no real need
-// for our trivial use case, with our general amount of data.
-func loadDatabase() error {
-	dbFile, err := os.Open(dbPath)
-	if err != nil {
-		return err
-	}
-	if err := json.NewDecoder(dbFile).Decode(&db); err != nil {
-		return err
-	}
-
-	// Further validate the database.
-	if db.Prefix == "" {
-		return errors.New("misconfigured prefix")
-	}
-
-	// Construct indexes for primary keys, validate against duplicates.
-	for _, pv := range db.Series {
-		if _, ok := indexSeries[pv.Prefix]; ok {
-			return fmt.Errorf("duplicate series: %s", pv.Prefix)
-		}
-		indexSeries[pv.Prefix] = pv
-	}
-	for _, pv := range db.Containers {
-		id := pv.Id()
-		if _, ok := indexContainer[id]; ok {
-			return fmt.Errorf("duplicate container: %s", id)
-		}
-		indexContainer[id] = pv
-	}
-
-	// Construct an index that goes from parent containers to their children.
-	for _, pv := range db.Containers {
-		if pv.Parent == "" {
-			continue
-		}
-		if _, ok := indexContainer[pv.Parent]; !ok {
-			return fmt.Errorf("container %s has a nonexistent parent %s",
-				pv.Id(), pv.Parent)
-		}
-		indexChildren[pv.Parent] = append(indexChildren[pv.Parent], pv)
-	}
-
-	// Validate that no container is a parent of itself on any level.
-	for _, pv := range db.Containers {
-		parents := map[ContainerId]bool{pv.Id(): true}
-		for pv.Parent != "" {
-			if parents[pv.Parent] {
-				return fmt.Errorf("%s contains itself", pv.Parent)
-			}
-			parents[pv.Parent] = true
-			pv = indexContainer[pv.Parent]
-		}
-	}
-
-	// Open database log file for appending.
-	if dbLog, err = os.OpenFile(dbPath+".log",
-		os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0644); err != nil {
-		return err
-	}
-
-	// Remember the current state of the database.
-	dbLast = db
-	return nil
-}
-
 func main() {
 	if len(os.Args) != 3 {
 		log.Fatalf("usage: %s ADDRESS DATABASE\n", os.Args[0])
@@ -170,6 +34,9 @@ func main() {
 		log.Fatalln(err)
 	}
 
+	// TODO: Eventually we will need to load a font file for label printing.
+	//  - The path might be part of configuration, or implicit by filename.
+
 	// TODO: Some routing, don't forget about sessions.
 	//  - https://stackoverflow.com/a/33880971/76313
 	//