Add Download() function, for retrieving a remote database file

README.md

@@ -12,13 +12,13 @@ A Go library for accessing and using SQLite databases stored remotely on DBHub.i
 * List the columns present in a table or view, along with their details
 * List the branches of a database
 * Generate diffs between two databases, or database revisions
+* Download a complete database
 
 ### Still to do
 
 * Tests for each function
 * Retrieve index details for a database
 * Return the list of available databases
-* Download a complete database
 * Upload a complete database
 * Retrieve database commit history details (size, branch, commit list, whatever else is useful)
 * Investigate what would be needed for this to work through the Go SQL API
@@ -134,5 +134,6 @@ ORDER BY table1.id;
 * [Retrieve column details](https://github.com/sqlitebrowser/go-dbhub/blob/master/examples/column_details/main.go) - Retrieve the details of columns in a table
 * [List branches](https://github.com/sqlitebrowser/go-dbhub/blob/master/examples/list_branches/main.go) - List all branches of a database
 * [Generate diff between two revisions](https://github.com/sqlitebrowser/go-dbhub/blob/master/examples/diff_commits/main.go) - Figure out the differences between two databases or two versions of one database
+* [Download database](https://github.com/sqlitebrowser/go-dbhub/blob/master/examples/download_database/main.go) - Download the complete database file
 
 Please try it out, submits PRs to extend or fix things, and report any weirdness or bugs you encounter. :smile:

dbhub.go

@@ -5,6 +5,7 @@ package dbhub
 import (
 	"encoding/base64"
 	"fmt"
+	"io"
 	"net/url"
 
 	com "github.com/sqlitebrowser/dbhub.io/common"
@@ -45,7 +46,7 @@ func (c Connection) Branches(dbowner, dbname string) (branches map[string]com.Br
 	// Fetch the list of branches and the default branch
 	var response com.BranchListResponseContainer
 	queryUrl := c.Server + "/v1/branches"
-	err = sendRequest(queryUrl, data, &response)
+	err = sendRequestJSON(queryUrl, data, &response)
 
 	// Extract information for return values
 	branches = response.Entries
@@ -61,7 +62,7 @@ func (c Connection) Columns(dbOwner, dbName string, ident Identifier, table stri
 
 	// Fetch the list of columns
 	queryUrl := c.Server + "/v1/columns"
-	err = sendRequest(queryUrl, data, &columns)
+	err = sendRequestJSON(queryUrl, data, &columns)
 	return
 }
 
@@ -109,7 +110,21 @@ func (c Connection) Diff(dbOwnerA, dbNameA string, identA Identifier, dbOwnerB,
 
 	// Fetch the diffs
 	queryUrl := c.Server + "/v1/diff"
-	err = sendRequest(queryUrl, data, &diffs)
+	err = sendRequestJSON(queryUrl, data, &diffs)
+	return
+}
+
+// Download returns the database file
+func (c Connection) Download(dbOwner, dbName string, ident Identifier) (db io.ReadCloser, err error) {
+	// Prepare the API parameters
+	data := c.PrepareVals(dbOwner, dbName, ident)
+
+	// Fetch the database file
+	queryUrl := c.Server + "/v1/download"
+	db, err = sendRequest(queryUrl, data)
+	if err != nil {
+		return
+	}
 	return
 }
 
@@ -120,7 +135,7 @@ func (c Connection) Indexes(dbOwner, dbName string, ident Identifier) (idx map[s
 
 	// Fetch the list of indexes
 	queryUrl := c.Server + "/v1/indexes"
-	err = sendRequest(queryUrl, data, &idx)
+	err = sendRequestJSON(queryUrl, data, &idx)
 	return
 }
 
@@ -158,7 +173,7 @@ func (c Connection) Query(dbOwner, dbName string, ident Identifier, blobBase64 b
 	// Run the query on the remote database
 	var returnedData []com.DataRow
 	queryUrl := c.Server + "/v1/query"
-	err = sendRequest(queryUrl, data, &returnedData)
+	err = sendRequestJSON(queryUrl, data, &returnedData)
 	if err != nil {
 		return
 	}
@@ -204,7 +219,7 @@ func (c Connection) Tables(dbOwner, dbName string, ident Identifier) (tbl []stri
 
 	// Fetch the list of tables
 	queryUrl := c.Server + "/v1/tables"
-	err = sendRequest(queryUrl, data, &tbl)
+	err = sendRequestJSON(queryUrl, data, &tbl)
 	return
 }
 
@@ -215,6 +230,6 @@ func (c Connection) Views(dbOwner, dbName string, ident Identifier) (views []str
 
 	// Fetch the list of views
 	queryUrl := c.Server + "/v1/views"
-	err = sendRequest(queryUrl, data, &views)
+	err = sendRequestJSON(queryUrl, data, &views)
 	return
 }

examples/download_database/main.go

@@ -0,0 +1,35 @@
+package main
+
+import (
+	"fmt"
+	"io/ioutil"
+	"log"
+
+	"github.com/sqlitebrowser/go-dbhub"
+)
+
+func main() {
+	// Create a new DBHub.io API object
+	db, err := dbhub.New("YOUR_API_KEY_HERE")
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	// Retrieve the remote database file
+	dbName := "Join Testing.sqlite"
+	dbStream, err := db.Download("justinclift", dbName, dbhub.Identifier{})
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	// Save the database file in the current directory
+	buf, err := ioutil.ReadAll(dbStream)
+	if err != nil {
+		log.Fatal(err)
+	}
+	err = ioutil.WriteFile(dbName, buf, 0644)
+	if err != nil {
+		log.Fatal(err)
+	}
+	fmt.Printf("Saved database file as '%s'\n", dbName)
+}

http.go

@@ -3,14 +3,32 @@ package dbhub
 import (
 	"encoding/json"
 	"fmt"
+	"io"
 	"net/http"
 	"net/url"
 	"strings"
 )
 
-// sendRequest sends the query to the server.  It exists because http.PostForm() doesn't seem to have a way
-// to change header values.
-func sendRequest(queryUrl string, data url.Values, returnStructure interface{}) (err error) {
+// sendRequestJSON sends a request to DBHub.io, formatting the returned result as JSON
+func sendRequestJSON(queryUrl string, data url.Values, returnStructure interface{}) (err error) {
+	// Send the request
+	var body io.ReadCloser
+	body, err = sendRequest(queryUrl, data)
+	if err != nil {
+		return
+	}
+
+	// Unmarshall the JSON response into the structure provided by the caller
+	err = json.NewDecoder(body).Decode(returnStructure)
+	if err != nil {
+		return
+	}
+	return
+}
+
+// sendRequest sends a request to DBHub.io.  It exists because http.PostForm() doesn't seem to have a way of changing
+// header values.
+func sendRequest(queryUrl string, data url.Values) (body io.ReadCloser, err error) {
 	var req *http.Request
 	var resp *http.Response
 	var client http.Client
@@ -35,10 +53,7 @@ func sendRequest(queryUrl string, data url.Values, returnStructure interface{})
 		return
 	}
 
-	// Unmarshall the JSON response into the structure provided by the caller
-	err = json.NewDecoder(resp.Body).Decode(returnStructure)
-	if err != nil {
-		return
-	}
+	// Return the response body
+	body = resp.Body
 	return
 }