" + shortenURL + "") } - mu.Lock() - urls[key] = urlValue.String() - mu.Unlock() - ctx.SetStatusCode(iris.StatusOK) - shortenURL := "http://" + app.Config.VHost + "/url/" + key - data["form_result"] = template.HTML("
Here is your short URL: " + shortenURL + "") - } + } } + data["url_count"] = db.Len() ctx.Render("index.html", data) }) @@ -113,10 +117,178 @@ func main() { // +------------------------------------------------------------+ // | | -// | Random String | +// | Store | // | | // +------------------------------------------------------------+ +// Panic panics, change it if you don't want to panic on critical INITIALIZE-ONLY-ERRORS +var Panic = func(v interface{}) { + panic(v) +} + +// Store is the store interface for urls. +// Note: no Del functionality. +type Store interface { + Set(key string, value string) error // error if something went wrong + Get(key string) string // empty value if not found + Len() int // should return the number of all the records/tables/buckets + Close() error // release the store or ignore +} + +var ( + tableURLs = []byte("urls") +) + +// DB representation of a Store. +// Only one table/bucket which contains the urls, so it's not a fully Database, +// it works only with single bucket because that all we need. +type DB struct { + db *bolt.DB +} + +var _ Store = &DB{} + +// openDatabase open a new database connection +// and returns its instance. +func openDatabase(stumb string) *bolt.DB { + // Open the data(base) file in the current working directory. + // It will be created if it doesn't exist. + db, err := bolt.Open(stumb, 0600, nil) + if err != nil { + Panic(err) + } + + // create the buckets here + var tables = [...][]byte{ + tableURLs, + } + + db.Update(func(tx *bolt.Tx) (err error) { + for _, table := range tables { + _, err = tx.CreateBucketIfNotExists(table) + if err != nil { + Panic(err) + } + } + + return + }) + + return db +} + +// NewDB returns a new DB instance, its connection is opened. +// DB implements the Store. +func NewDB(stumb string) *DB { + return &DB{ + db: openDatabase(stumb), + } +} + +// Set sets a shorten url and its key +// Note: Caller is responsible to generate a key. +func (d *DB) Set(key string, value string) error { + d.db.Update(func(tx *bolt.Tx) error { + b := tx.Bucket(tableURLs) + // Generate ID for the url + // Note: we could use that instead of a random string key + // but we want to simulate a real-world url shortener + // so we skip that. + // id, _ := b.NextSequence() + return b.Put([]byte(key), []byte(value)) + }) + return nil +} + +// Get returns a url by its key. +// +// Returns an empty string if not found. +func (d *DB) Get(key string) (value string) { + keyb := []byte(key) + d.db.View(func(tx *bolt.Tx) error { + b := tx.Bucket(tableURLs) + c := b.Cursor() + for k, v := c.First(); k != nil; k, v = c.Next() { + if bytes.Equal(keyb, k) { + value = string(v) + break + } + } + + return nil + }) + + return +} + +// Len returns all the "shorted" urls length +func (d *DB) Len() (num int) { + d.db.View(func(tx *bolt.Tx) error { + + // Assume bucket exists and has keys + b := tx.Bucket(tableURLs) + + b.ForEach(func([]byte, []byte) error { + num++ + return nil + }) + return nil + }) + return +} + +// Close the data(base) connection +func (d *DB) Close() error { + return d.db.Close() +} + +// +------------------------------------------------------------+ +// | | +// | Factory | +// | | +// +------------------------------------------------------------+ + +// Generator the type to generate keys(short urls) based on 'n' +type Generator func(n int) string + +// DefaultGenerator is the defautl url generator (the simple randomString) +var DefaultGenerator = randomString + +// Factory is responsible to generate keys(short urls) +type Factory struct { + store Store + generator Generator +} + +// NewFactory receives a generator and a store and returns a new url Factory. +func NewFactory(generator Generator, store Store) *Factory { + return &Factory{ + store: store, + generator: generator, + } +} + +// Gen generates the key. +func (f *Factory) Gen(uri string) (key string, err error) { + // we don't return the parsed url because #hash are converted to uri-compatible + // and we don't want to encode/decode all the time, there is no need for that, + // we save the url as the user expects if the uri validation passed. + _, err = url.ParseRequestURI(uri) + if err != nil { + return "", err + } + key = f.generator(len(uri)) + // Make sure that the key is unique + for { + if v := f.store.Get(key); v == "" { + break + } + key = f.generator((len(uri) / 2) + 1) + } + + return key, nil +} + const ( letterBytes = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ" letterIdxBits = 6 // 6 bits to represent a letter index diff --git a/_examples/examples/url-shortener/static_files/style.css b/_examples/examples/url-shortener/resources/css/style.css similarity index 100% rename from _examples/examples/url-shortener/static_files/style.css rename to _examples/examples/url-shortener/resources/css/style.css diff --git a/_examples/examples/url-shortener/shortener.go b/_examples/examples/url-shortener/shortener.go new file mode 100644 index 00000000..dd6419ba --- /dev/null +++ b/_examples/examples/url-shortener/shortener.go @@ -0,0 +1,4 @@ +package main + +// Version is the current version of the url-shortener package. +const Version = "0.0.1" diff --git a/_examples/examples/url-shortener/templates/index.html b/_examples/examples/url-shortener/templates/index.html index 136f5152..8d4acfca 100644 --- a/_examples/examples/url-shortener/templates/index.html +++ b/_examples/examples/url-shortener/templates/index.html @@ -9,12 +9,13 @@
{{ .url_count }} URLs shortened
+ {{ if isPositive .url_count }} +{{ .url_count }} URLs shortened
+ {{ end }}