contentdb file.ext to content-type lookups

master
Anand Babu (AB) Periasamy 9 years ago
parent 5b18c787f0
commit 25df427383
  1. 26
      pkg/contentdb/Makefile
  2. 109
      pkg/contentdb/contentdb.go
  3. 46
      pkg/contentdb/contentdb_test.go
  4. 237
      pkg/contentdb/db.go

@ -0,0 +1,26 @@
# Generate db.go from db.json downloaded nodejs mime-db project.
# NOTE: Autogenerated db.go needs to be vet proofed. \
Manually edit json -> JSON for all variable names
all: checkdeps download build
# go-bindata generates go source from any data file.
checkdeps:
@go get -u github.com/jteeuwen/go-bindata/...
# Download db.json from NodeJS's mime-db project. It is under MIT license.
download: checkdeps
@mkdir db
@wget -nv https://cdn.rawgit.com/jshttp/mime-db/master/db.json -O db/db.json
# After generating db.go, clean up downloaded db.json.
build: download
@go-bindata -pkg contentdb -o db.go db
@rm -fv db/db.json
@rm -rfv db
# Clean auto-generated files and backups.
clean:
@rm -rf db.go
@rm -f *~

@ -0,0 +1,109 @@
/*
* mime-db: Mime Database, (C) 2015 Minio, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
// Package contentdb is a database of file extension to mime content-type.
// Definitions are imported from NodeJS mime-db project under MIT license.
package contentdb
import (
"fmt"
"strings"
"encoding/json"
)
var (
// Make note of initialization.
isInitialized = false
// Database of extension:content-type.
extDB map[string]string
)
// Load JSON data from gobindata and parse them into extDB.
func loadDB() error {
// Structure of JSON data from mime-db project.
type dbEntry struct {
Source string `json:"source"`
Compressible bool `json:"compresible"`
Extensions []string `json:"extensions"`
}
// Access embedded "db.json" inside go-bindata.
jsonDB, e := Asset("db/db.json")
if e != nil {
return e
}
// Convert db.json into go's typed structure.
db := make(map[string]dbEntry)
if e := json.Unmarshal(jsonDB, &db); e != nil {
return e
}
// Generate a new database from mime-db.
for key, val := range db {
if len(val.Extensions) > 0 {
/* Denormalize - each extension has its own
unique content-type now. Looks will be fast. */
for _, ext := range val.Extensions {
/* Single extension type may map to
multiple content-types. In that case,
simply prefer the longest content-type
to maintain some level of
consistency. Only guarantee is,
whatever content type is assigned, it
is appropriate and valid type. */
if strings.Compare(extDB[ext], key) < 0 {
extDB[ext] = key
}
}
}
}
return nil
}
// Init initializes contentdb for lookups. JSON structure is parsed into a simple map of extension and content-type.
func Init() error {
var e error
extDB = make(map[string]string)
if !isInitialized {
e = loadDB()
}
isInitialized = true
return e
}
// Lookup returns matching content-type for known types of file extensions.
func Lookup(extension string) (contentType string, e error) {
if !isInitialized {
e = Init()
}
return extDB[extension], e
}
// MustLookup returns matching content-type for known types of file extensions. In case of error, it panics.
func MustLookup(extension string) (contentType string) {
if !isInitialized {
if e := Init(); e != nil {
panic(fmt.Sprintf("Error loading contentdb: %s\n", e))
}
}
return extDB[extension]
}

@ -0,0 +1,46 @@
/*
* mime-db: Mime Database, (C) 2015 Minio, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package contentdb_test
import (
"testing"
"github.com/minio/minio/pkg/contentdb"
. "gopkg.in/check.v1"
)
func Test(t *testing.T) { TestingT(t) }
type MySuite struct{}
var _ = Suite(&MySuite{})
func (s *MySuite) TestLookup(c *C) {
// Test initializing.
e := contentdb.Init()
c.Assert(e, IsNil)
// Test MustLookup.
contentType, e := contentdb.Lookup("exe")
c.Assert(e, IsNil)
c.Assert(contentType, Not(Equals), "")
// Test MustLookup.
contentType = contentdb.MustLookup("exe")
c.Assert(contentType, Not(Equals), "")
}

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