api: Add diff handler to v1 API

This adds a /v1/diff handler which calls the com.Diff function and
returns its results in JSON format. While this might be useful later its
main purpose at the moment is to expose the com.Diff function in an easy
to call way for testing purposes. Because of this the API handler is not
added to the help page yet.

Author: MKleusberg

api/handlers.go

@@ -5,6 +5,7 @@ import (
 	"fmt"
 	"log"
 	"net/http"
+	"net/url"
 
 	sqlite "github.com/gwenn/gosqlite"
 	com "github.com/sqlitebrowser/dbhub.io/common"
@@ -249,3 +250,109 @@ func viewsHandler(w http.ResponseWriter, r *http.Request) {
 	}
 	fmt.Fprintf(w, string(jsonData))
 }
+
+// diffHandler generates a diff between two databases or two versions of a database
+// This can be run from the command line using curl, like this:
+//   $ curl -F apikey="YOUR_API_KEY_HERE" -F dbowner_a="justinclift" -F dbname_a="Join Testing.sqlite" -F commit_a="ea12..." -F commit_b="5a7c..." https://api.dbhub.io/v1/diff
+//   * "apikey" is one of your API keys.  These can be generated from your Settings page once logged in
+//   * "dbowner_a" is the owner of the first database being diffed
+//   * "dbname_a" is the name of the first database being diffed
+//   * "dbowner_b" is the owner of the second database being diffed (optional, if not provided same as first owner)
+//   * "dbname_b" is the name of the second database being diffed (optional, if not provided same as first name)
+//   * "commit_a" is the first commit for diffing
+//   * "commit_b" is the second commit for diffing
+func diffHandler(w http.ResponseWriter, r *http.Request) {
+	loggedInUser, err := checkAuth(w, r)
+	if err != nil {
+		jsonErr(w, err.Error(), http.StatusUnauthorized)
+		return
+	}
+
+	// Retrieve owner, name, and commit ids
+	oa := r.PostFormValue("dbowner_a")
+	na := r.PostFormValue("dbname_a")
+	ca := r.PostFormValue("commit_a")
+	ob := r.PostFormValue("dbowner_a")
+	nb := r.PostFormValue("dbname_b")
+	cb := r.PostFormValue("commit_b")
+
+	// If no primary database owner and name are given or if no commit ids are given, return
+	if oa == "" || na == "" || ca == "" || cb == "" {
+		jsonErr(w, err.Error(), http.StatusBadRequest)
+		return
+	}
+
+	// If no secondary database owner and name are provided, use the ones of the first database
+	if ob == "" || nb == "" {
+		ob = oa
+		nb = na
+	}
+
+	// Unescape, then validate the owner and database names and commit ids
+	dbOwnerA, err := url.QueryUnescape(oa)
+	if err != nil {
+		jsonErr(w, err.Error(), http.StatusBadRequest)
+		return
+	}
+	dbOwnerB, err := url.QueryUnescape(ob)
+	if err != nil {
+		jsonErr(w, err.Error(), http.StatusBadRequest)
+		return
+	}
+	dbNameA, err := url.QueryUnescape(na)
+	if err != nil {
+		jsonErr(w, err.Error(), http.StatusBadRequest)
+		return
+	}
+	dbNameB, err := url.QueryUnescape(nb)
+	if err != nil {
+		jsonErr(w, err.Error(), http.StatusBadRequest)
+		return
+	}
+	err = com.ValidateUser(dbOwnerA)
+	if err != nil {
+		jsonErr(w, err.Error(), http.StatusBadRequest)
+		return
+	}
+	err = com.ValidateUser(dbOwnerB)
+	if err != nil {
+		jsonErr(w, err.Error(), http.StatusBadRequest)
+		return
+	}
+	err = com.ValidateDB(dbNameA)
+	if err != nil {
+		jsonErr(w, err.Error(), http.StatusBadRequest)
+		return
+	}
+	err = com.ValidateDB(dbNameB)
+	if err != nil {
+		jsonErr(w, err.Error(), http.StatusBadRequest)
+		return
+	}
+	err = com.ValidateCommitID(ca)
+	if err != nil {
+		jsonErr(w, err.Error(), http.StatusBadRequest)
+		return
+	}
+	err = com.ValidateCommitID(cb)
+	if err != nil {
+		jsonErr(w, err.Error(), http.StatusBadRequest)
+		return
+	}
+
+	// Perform diff
+	diffs, err := com.Diff(dbOwnerA, "/", dbNameA, ca, dbOwnerB, "/", dbNameB, cb, loggedInUser)
+	if err != nil {
+		jsonErr(w, err.Error(), http.StatusInternalServerError)
+		return
+	}
+
+	// Return the results
+	jsonData, err := json.Marshal(diffs)
+	if err != nil {
+		log.Printf("Error when JSON marshalling returned data in diffHandler(): %v\n", err)
+		jsonErr(w, err.Error(), http.StatusInternalServerError)
+		return
+	}
+	fmt.Fprintf(w, string(jsonData))
+}

api/main.go

@@ -80,6 +80,7 @@ func main() {
 	http.Handle("/v1/query", gz.GzipHandler(handleWrapper(queryHandler)))
 	http.Handle("/v1/tables", gz.GzipHandler(handleWrapper(tablesHandler)))
 	http.Handle("/v1/views", gz.GzipHandler(handleWrapper(viewsHandler)))
+	http.Handle("/v1/diff", gz.GzipHandler(handleWrapper(diffHandler)))
 
 	// Generate the formatted server string
 	server = fmt.Sprintf("https://%s", com.Conf.Api.ServerName)