Refactor: generic handlers

characteristics.go

@@ -4,18 +4,16 @@ import (
 	"encoding/json"
 	"errors"
 	"fmt"
-	"net/http"
-	"strconv"
 	"strings"
 	"time"
-
-	"github.com/gorilla/mux"
 )
 
 func init() {
 	DB.AddTableWithName(CharacteristicBase{}, "characteristics").SetKeys(true, "Id")
 }
 
+type CharacteristicService struct{}
+
 // A Characteristic is a lookup type
 type CharacteristicBase struct {
 	Id                   int64     `json:"id,omitempty"`
@@ -36,67 +34,25 @@ type Characteristic struct {
 	CharacteristicTypeName string         `db:"characteristic_type_name" json:"characteristicType"`
 }
 
+type Characteristics []*Characteristic
+
 type CharacteristicJSON struct {
 	Characteristic *Characteristic `json:"characteristic"`
 }
 
 type CharacteristicsJSON struct {
-	Characteristics []*Characteristic `json:"characteristics"`
+	Characteristics *Characteristics `json:"characteristics"`
 }
 
-type CharacteristicListOptions struct {
+func (c *Characteristic) marshal() ([]byte, error) {
-	ListOptions
+	return json.Marshal(&CharacteristicJSON{Characteristic: c})
-	Genus string
 }
 
-func serveCharacteristicsList(w http.ResponseWriter, r *http.Request) {
+func (c *Characteristics) marshal() ([]byte, error) {
-	var opt CharacteristicListOptions
+	return json.Marshal(&CharacteristicsJSON{Characteristics: c})
-	if err := schemaDecoder.Decode(&opt, r.URL.Query()); err != nil {
-		http.Error(w, err.Error(), http.StatusInternalServerError)
-		return
-	}
-
-	opt.Genus = mux.Vars(r)["genus"]
-
-	characteristics, err := dbGetCharacteristics(&opt)
-	if err != nil {
-		http.Error(w, err.Error(), http.StatusInternalServerError)
-		return
-	}
-	if characteristics == nil {
-		characteristics = []*Characteristic{}
-	}
-	data, err := json.Marshal(CharacteristicsJSON{Characteristics: characteristics})
-	if err != nil {
-		http.Error(w, err.Error(), http.StatusInternalServerError)
-		return
-	}
-	w.Header().Set("Content-Type", "application/json; charset=UTF-8")
-	w.Write(data)
 }
 
-func serveCharacteristic(w http.ResponseWriter, r *http.Request) {
+func (c CharacteristicService) list(opt *ListOptions) (entity, error) {
-	id, err := strconv.ParseInt(mux.Vars(r)["Id"], 10, 0)
-	if err != nil {
-		http.Error(w, err.Error(), http.StatusInternalServerError)
-		return
-	}
-
-	characteristic, err := dbGetCharacteristic(id)
-	if err != nil {
-		http.Error(w, err.Error(), http.StatusInternalServerError)
-		return
-	}
-	data, err := json.Marshal(CharacteristicJSON{Characteristic: characteristic})
-	if err != nil {
-		http.Error(w, err.Error(), http.StatusInternalServerError)
-		return
-	}
-	w.Header().Set("Content-Type", "application/json; charset=UTF-8")
-	w.Write(data)
-}
-
-func dbGetCharacteristics(opt *CharacteristicListOptions) ([]*Characteristic, error) {
 	if opt == nil {
 		return nil, errors.New("must provide options")
 	}
@@ -123,15 +79,15 @@ func dbGetCharacteristics(opt *CharacteristicListOptions) ([]*Characteristic, er
 
 	sql += " GROUP BY c.id, ct.characteristic_type_name;"
 
-	var characteristics []*Characteristic
+	var characteristics Characteristics
 	err := DBH.Select(&characteristics, sql, vals...)
 	if err != nil {
 		return nil, err
 	}
-	return characteristics, nil
+	return &characteristics, nil
 }
 
-func dbGetCharacteristic(id int64) (*Characteristic, error) {
+func (c CharacteristicService) get(id int64, dummy string) (entity, error) {
 	var characteristic Characteristic
 	sql := `SELECT c.*, ct.characteristic_type_name,
 			array_agg(m.id) AS measurements, array_agg(st.id) AS strains

entities.go

@@ -0,0 +1,18 @@
+package main
+
+type entity interface {
+	marshal() ([]byte, error)
+}
+
+type getter interface {
+	get(int64, string) (entity, error)
+}
+
+type lister interface {
+	list(*ListOptions) (entity, error)
+}
+
+type updater interface {
+	update(int64, *entity, Claims) error
+	unmarshal([]byte) (entity, error)
+}

handlers.go

@@ -3,8 +3,10 @@ package main
 import (
 	"encoding/json"
 	"errors"
+	"io/ioutil"
 	"net/http"
 	"os"
+	"strconv"
 	"strings"
 	"time"
 
@@ -83,13 +85,13 @@ func Handler() http.Handler {
 	}
 
 	routes := []r{
-		r{serveStrainsList, "GET", "/strains"},
+		r{handleLister(StrainService{}), "GET", "/strains"},
-		r{serveStrain, "GET", "/strains/{Id:.+}"},
+		r{handleGetter(StrainService{}), "GET", "/strains/{Id:.+}"},
-		r{serveUpdateStrain, "PUT", "/strains/{Id:.+}"},
+		r{handleUpdater(StrainService{}), "PUT", "/strains/{Id:.+}"},
-		r{serveMeasurementsList, "GET", "/measurements"},
+		r{handleLister(MeasurementService{}), "GET", "/measurements"},
-		r{serveMeasurement, "GET", "/measurements/{Id:.+}"},
+		r{handleGetter(MeasurementService{}), "GET", "/measurements/{Id:.+}"},
-		r{serveCharacteristicsList, "GET", "/characteristics"},
+		r{handleLister(CharacteristicService{}), "GET", "/characteristics"},
-		r{serveCharacteristic, "GET", "/characteristics/{Id:.+}"},
+		r{handleGetter(CharacteristicService{}), "GET", "/characteristics/{Id:.+}"},
 	}
 
 	for _, route := range routes {
@@ -99,6 +101,93 @@ func Handler() http.Handler {
 	return corsHandler(m)
 }
 
+func handleGetter(g getter) http.HandlerFunc {
+	return func(w http.ResponseWriter, r *http.Request) {
+		id, err := strconv.ParseInt(mux.Vars(r)["Id"], 10, 0)
+		if err != nil {
+			http.Error(w, err.Error(), http.StatusInternalServerError)
+			return
+		}
+
+		e, err := g.get(id, mux.Vars(r)["genus"])
+		if err != nil {
+			http.Error(w, err.Error(), http.StatusInternalServerError)
+			return
+		}
+
+		data, err := e.marshal()
+		if err != nil {
+			http.Error(w, err.Error(), http.StatusInternalServerError)
+			return
+		}
+		w.Header().Set("Content-Type", "application/json; charset=UTF-8")
+		w.Write(data)
+	}
+}
+
+func handleLister(l lister) http.HandlerFunc {
+	return func(w http.ResponseWriter, r *http.Request) {
+		var opt ListOptions
+		if err := schemaDecoder.Decode(&opt, r.URL.Query()); err != nil {
+			http.Error(w, err.Error(), http.StatusInternalServerError)
+			return
+		}
+
+		opt.Genus = mux.Vars(r)["genus"]
+
+		es, err := l.list(&opt)
+		if err != nil {
+			http.Error(w, err.Error(), http.StatusInternalServerError)
+			return
+		}
+		data, err := es.marshal()
+		if err != nil {
+			http.Error(w, err.Error(), http.StatusInternalServerError)
+		}
+		w.Header().Set("Content-Type", "application/json; charset=UTF-8")
+		w.Write(data)
+	}
+}
+
+func handleUpdater(u updater) http.HandlerFunc {
+	return func(w http.ResponseWriter, r *http.Request) {
+		id, err := strconv.ParseInt(mux.Vars(r)["Id"], 10, 0)
+		if err != nil {
+			http.Error(w, err.Error(), http.StatusInternalServerError)
+			return
+		}
+
+		bodyBytes, err := ioutil.ReadAll(r.Body)
+		if err != nil {
+			http.Error(w, err.Error(), http.StatusInternalServerError)
+			return
+		}
+
+		e, err := u.unmarshal(bodyBytes)
+		if err != nil {
+			http.Error(w, err.Error(), http.StatusInternalServerError)
+			return
+		}
+
+		c := context.Get(r, "claims")
+		var claims Claims = c.(Claims)
+
+		err = u.update(id, &e, claims)
+		if err != nil {
+			http.Error(w, err.Error(), http.StatusInternalServerError)
+			return
+		}
+
+		data, err := e.marshal()
+		if err != nil {
+			http.Error(w, err.Error(), http.StatusInternalServerError)
+			return
+		}
+		w.Header().Set("Content-Type", "application/json; charset=UTF-8")
+		w.Write(data)
+	}
+}
+
 func tokenHandler(h http.Handler) http.Handler {
 	token := func(w http.ResponseWriter, r *http.Request) {
 		w.Header().Set("Content-Type", "application/json; charset=UTF-8")

helpers.go

@@ -11,6 +11,7 @@ type ListOptions struct {
 	PerPage int   `url:",omitempty" json:",omitempty"`
 	Page    int   `url:",omitempty" json:",omitempty"`
 	Ids     []int `url:",omitempty" json:",omitempty" schema:"ids[]"`
+	Genus   string
 }
 
 func (o ListOptions) PageOrDefault() int {

measurements.go

@@ -4,12 +4,8 @@ import (
 	"encoding/json"
 	"errors"
 	"fmt"
-	"net/http"
-	"strconv"
 	"strings"
 	"time"
-
-	"github.com/gorilla/mux"
 )
 
 var ErrMeasurementNotFound = errors.New("measurement not found")
@@ -18,6 +14,8 @@ func init() {
 	DB.AddTableWithName(MeasurementBase{}, "measurements").SetKeys(true, "Id")
 }
 
+type MeasurementService struct{}
+
 // There are three types of supported measurements: fixed-test, free-text,
 // & numerical. The table has a constraint that will allow one or the other
 // for a particular combination of strain & characteristic, but not both.
@@ -48,67 +46,25 @@ type Measurement struct {
 	TestMethod          NullString `db:"test_method_name" json:"testMethod"`
 }
 
+type Measurements []*Measurement
+
 type MeasurementJSON struct {
 	Measurement *Measurement `json:"measurement"`
 }
 
 type MeasurementsJSON struct {
-	Measurements []*Measurement `json:"measurements"`
+	Measurements *Measurements `json:"measurements"`
 }
 
-type MeasurementListOptions struct {
+func (m *Measurement) marshal() ([]byte, error) {
-	ListOptions
+	return json.Marshal(&MeasurementJSON{Measurement: m})
-	Genus string
 }
 
-func serveMeasurementsList(w http.ResponseWriter, r *http.Request) {
+func (m *Measurements) marshal() ([]byte, error) {
-	var opt MeasurementListOptions
+	return json.Marshal(&MeasurementsJSON{Measurements: m})
-	if err := schemaDecoder.Decode(&opt, r.URL.Query()); err != nil {
-		http.Error(w, err.Error(), http.StatusInternalServerError)
-		return
-	}
-
-	opt.Genus = mux.Vars(r)["genus"]
-
-	measurements, err := dbGetMeasurements(&opt)
-	if err != nil {
-		http.Error(w, err.Error(), http.StatusInternalServerError)
-		return
-	}
-	if measurements == nil {
-		measurements = []*Measurement{}
-	}
-	data, err := json.Marshal(MeasurementsJSON{Measurements: measurements})
-	if err != nil {
-		http.Error(w, err.Error(), http.StatusInternalServerError)
-		return
-	}
-	w.Header().Set("Content-Type", "application/json; charset=UTF-8")
-	w.Write(data)
 }
 
-func serveMeasurement(w http.ResponseWriter, r *http.Request) {
+func (m MeasurementService) list(opt *ListOptions) (entity, error) {
-	id, err := strconv.ParseInt(mux.Vars(r)["Id"], 10, 0)
-	if err != nil {
-		http.Error(w, err.Error(), http.StatusInternalServerError)
-		return
-	}
-
-	measurement, err := dbGetMeasurement(id, mux.Vars(r)["genus"])
-	if err != nil {
-		http.Error(w, err.Error(), http.StatusInternalServerError)
-		return
-	}
-	data, err := json.Marshal(MeasurementJSON{Measurement: measurement})
-	if err != nil {
-		http.Error(w, err.Error(), http.StatusInternalServerError)
-		return
-	}
-	w.Header().Set("Content-Type", "application/json; charset=UTF-8")
-	w.Write(data)
-}
-
-func dbGetMeasurements(opt *MeasurementListOptions) ([]*Measurement, error) {
 	if opt == nil {
 		return nil, errors.New("must provide options")
 	}
@@ -142,15 +98,15 @@ func dbGetMeasurements(opt *MeasurementListOptions) ([]*Measurement, error) {
 
 	sql += ";"
 
-	var measurements []*Measurement
+	var measurements Measurements
 	err := DBH.Select(&measurements, sql, vals...)
 	if err != nil {
 		return nil, err
 	}
-	return measurements, nil
+	return &measurements, nil
 }
 
-func dbGetMeasurement(id int64, genus string) (*Measurement, error) {
+func (m MeasurementService) get(id int64, genus string) (entity, error) {
 	var measurement Measurement
 	sql := `SELECT m.*, c.characteristic_name,
 		t.text_measurement_name AS text_measurement_type_name,

strains.go

@@ -5,12 +5,7 @@ import (
 	"encoding/json"
 	"errors"
 	"fmt"
-	"net/http"
-	"strconv"
 	"strings"
-
-	"github.com/gorilla/context"
-	"github.com/gorilla/mux"
 )
 
 var (
@@ -22,6 +17,8 @@ func init() {
 	DB.AddTableWithName(StrainBase{}, "strains").SetKeys(true, "Id")
 }
 
+type StrainService struct{}
+
 // StrainBase is what the DB expects to see for inserts/updates
 type StrainBase struct {
 	Id               int64      `db:"id" json:"id"`
@@ -45,105 +42,34 @@ type Strain struct {
 	*StrainBase
 	SpeciesName       string         `db:"species_name" json:"speciesName"`
 	Measurements      NullSliceInt64 `db:"measurements" json:"measurements"`
-	TotalMeasurements int            `db:"total_measurements" json:"totalMeasurements"`
+	TotalMeasurements int64          `db:"total_measurements" json:"totalMeasurements"`
 }
 
+type Strains []*Strain
+
 type StrainJSON struct {
 	Strain *Strain `json:"strain"`
 }
 
 type StrainsJSON struct {
-	Strains []*Strain `json:"strains"`
+	Strains *Strains `json:"strains"`
 }
 
-type StrainListOptions struct {
+func (s *Strain) marshal() ([]byte, error) {
-	ListOptions
+	return json.Marshal(&StrainJSON{Strain: s})
-	Genus string
 }
 
-func serveStrainsList(w http.ResponseWriter, r *http.Request) {
+func (s *Strains) marshal() ([]byte, error) {
-	var opt StrainListOptions
+	return json.Marshal(&StrainsJSON{Strains: s})
-	if err := schemaDecoder.Decode(&opt, r.URL.Query()); err != nil {
-		http.Error(w, err.Error(), http.StatusInternalServerError)
-		return
-	}
-
-	opt.Genus = mux.Vars(r)["genus"]
-
-	strains, err := dbGetStrains(&opt)
-	if err != nil {
-		http.Error(w, err.Error(), http.StatusInternalServerError)
-		return
-	}
-	if strains == nil {
-		strains = []*Strain{}
-	}
-	data, err := json.Marshal(StrainsJSON{Strains: strains})
-	if err != nil {
-		http.Error(w, err.Error(), http.StatusInternalServerError)
-	}
-	w.Header().Set("Content-Type", "application/json; charset=UTF-8")
-	w.Write(data)
 }
 
-func serveStrain(w http.ResponseWriter, r *http.Request) {
+func (s StrainService) unmarshal(b []byte) (entity, error) {
-	id, err := strconv.ParseInt(mux.Vars(r)["Id"], 10, 0)
+	var sj StrainJSON
-	if err != nil {
+	err := json.Unmarshal(b, &sj)
-		http.Error(w, err.Error(), http.StatusInternalServerError)
+	return sj.Strain, err
-		return
-	}
-
-	strain, err := dbGetStrain(id, mux.Vars(r)["genus"])
-	if err != nil {
-		http.Error(w, err.Error(), http.StatusInternalServerError)
-		return
-	}
-
-	data, err := json.Marshal(StrainJSON{Strain: strain})
-	if err != nil {
-		http.Error(w, err.Error(), http.StatusInternalServerError)
-		return
-	}
-	w.Header().Set("Content-Type", "application/json; charset=UTF-8")
-	w.Write(data)
 }
 
-func serveUpdateStrain(w http.ResponseWriter, r *http.Request) {
+func (s StrainService) list(opt *ListOptions) (entity, error) {
-	id, err := strconv.ParseInt(mux.Vars(r)["Id"], 10, 0)
-	if err != nil {
-		http.Error(w, err.Error(), http.StatusInternalServerError)
-		return
-	}
-
-	var strainjson StrainJSON
-	err = json.NewDecoder(r.Body).Decode(&strainjson)
-	if err != nil {
-		http.Error(w, err.Error(), http.StatusInternalServerError)
-		return
-	}
-
-	c := context.Get(r, "claims")
-	var claims Claims = c.(Claims)
-	strainjson.Strain.UpdatedBy = claims.Sub
-	strainjson.Strain.UpdatedAt = currentTime()
-	strainjson.Strain.Id = id
-
-	err = dbUpdateStrain(strainjson.Strain)
-	if err != nil {
-		http.Error(w, err.Error(), http.StatusInternalServerError)
-		return
-	}
-
-	data, err := json.Marshal(StrainJSON{Strain: strainjson.Strain})
-	if err != nil {
-		http.Error(w, err.Error(), http.StatusInternalServerError)
-		return
-	}
-	w.Header().Set("Content-Type", "application/json; charset=UTF-8")
-	w.Write(data)
-}
-
-func dbGetStrains(opt *StrainListOptions) ([]*Strain, error) {
 	if opt == nil {
 		return nil, errors.New("must provide options")
 	}
@@ -171,15 +97,15 @@ func dbGetStrains(opt *StrainListOptions) ([]*Strain, error) {
 
 	sql += " GROUP BY st.id, sp.species_name;"
 
-	var strains []*Strain
+	var strains Strains
 	err := DBH.Select(&strains, sql, vals...)
 	if err != nil {
 		return nil, err
 	}
-	return strains, nil
+	return &strains, nil
 }
 
-func dbGetStrain(id int64, genus string) (*Strain, error) {
+func (s StrainService) get(id int64, genus string) (entity, error) {
 	var strain Strain
 	q := `SELECT st.*, sp.species_name, array_agg(m.id) AS measurements,
 		COUNT(m) AS total_measurements
@@ -198,13 +124,19 @@ func dbGetStrain(id int64, genus string) (*Strain, error) {
 	return &strain, nil
 }
 
-func dbUpdateStrain(strain *Strain) error {
+func (s StrainService) update(id int64, e *entity, claims Claims) error {
+	strain := (*e).(*Strain)
+	strain.UpdatedBy = claims.Sub
+	strain.UpdatedAt = currentTime()
+	strain.Id = id
+
 	var species_id struct{ Id int64 }
 	q := `SELECT id FROM species WHERE species_name = $1;`
 	if err := DBH.SelectOne(&species_id, q, strain.SpeciesName); err != nil {
 		return err
 	}
 	strain.StrainBase.SpeciesId = species_id.Id
+
 	count, err := DBH.Update(strain.StrainBase)
 	if err != nil {
 		return err