Implement basic configuration and storage structure

internal/pastes/deletion_token.go

@@ -0,0 +1,27 @@
+package pastes
+
+import (
+	"github.com/Lukaesebrot/pasty/internal/env"
+	"math/rand"
+	"strconv"
+)
+
+// deletionTokenContents represents the characters a deletion token may contain
+const deletionTokenContents = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789#+-.,"
+
+// generateDeletionToken generates a new deletion token
+func generateDeletionToken() (string, error) {
+	// Read the deletion token length
+	rawLength := env.Get("DELETION_TOKEN_LENGTH", "12")
+	length, err := strconv.Atoi(rawLength)
+	if err != nil {
+		return "", err
+	}
+
+	// Generate the deletion token
+	bytes := make([]byte, length)
+	for i := range bytes {
+		bytes[i] = deletionTokenContents[rand.Int63()%int64(len(deletionTokenContents))]
+	}
+	return string(bytes), nil
+}

internal/pastes/paste.go

@@ -1,6 +1,16 @@
 package pastes
 
-import "github.com/bwmarrin/snowflake"
+import (
+	"github.com/alexedwards/argon2id"
+	"github.com/bwmarrin/snowflake"
+)
+
+func init() {
+	snowflakeNode, _ = snowflake.NewNode(1)
+}
+
+// snowflakeNode holds the current snowflake node
+var snowflakeNode *snowflake.Node
 
 // Paste represents a saved paste
 type Paste struct {
@@ -9,3 +19,39 @@ type Paste struct {
 	SuggestedSyntaxType string       `json:"suggestedSyntaxType" bson:"suggestedSyntaxType"`
 	DeletionToken       string       `json:"deletionToken" bson:"deletionToken"`
 }
+
+// Create creates a new paste object using the given content
+func Create(content string) (*Paste, error) {
+	// TODO: Generate the suggested syntax type
+	suggestedSyntaxType := ""
+
+	// Generate the deletion token
+	deletionToken, err := generateDeletionToken()
+	if err != nil {
+		return nil, err
+	}
+
+	// Return the paste object
+	return &Paste{
+		ID:                  snowflakeNode.Generate(),
+		Content:             content,
+		SuggestedSyntaxType: suggestedSyntaxType,
+		DeletionToken:       deletionToken,
+	}, nil
+}
+
+// HashDeletionToken hashes the current deletion token of a paste
+func (paste *Paste) HashDeletionToken() error {
+	hash, err := argon2id.CreateHash(paste.DeletionToken, argon2id.DefaultParams)
+	if err != nil {
+		return err
+	}
+	paste.DeletionToken = hash
+	return nil
+}
+
+// CheckDeletionToken checks whether or not the given deletion token is correct
+func (paste *Paste) CheckDeletionToken(deletionToken string) bool {
+	match, err := argon2id.ComparePasswordAndHash(deletionToken, paste.DeletionToken)
+	return err != nil && match
+}