add common and model

app/common/response.go

@@ -0,0 +1,20 @@
+package common
+
+import "net/http"
+
+type APIResponse struct {
+	Code    int
+	Data    interface{}
+	Message string
+	Err     error
+}
+
+func NewBadResponse(code int, message string, err error) *APIResponse {
+	return &APIResponse{code, nil, message, err}
+}
+
+func NewGoodResponse(code int, data interface{}) *APIResponse {
+	return &APIResponse{code, data, "", nil}
+}
+
+var InvalidRequestResponse APIResponse = *NewBadResponse(http.StatusBadRequest, "invalid request", nil)

app/common/util.go

@@ -0,0 +1,23 @@
+package common
+
+import (
+	"errors"
+	"fmt"
+	"net/http"
+	"strconv"
+
+	"github.com/gorilla/mux"
+)
+
+func GetIDFromRequest(r *http.Request) (int64, error) {
+	vars := mux.Vars(r)
+	id, ok := vars["id"]
+	if !ok {
+		return 0, errors.New("id not found in request")
+	}
+	return strconv.ParseInt(id, 10, 64)
+}
+
+func WrapError(context string, e error) error {
+	return fmt.Errorf("%s: %s", context, e)
+}

app/model/group.go

@@ -0,0 +1,6 @@
+package model
+
+type GroupPost struct {
+	Groupname string   `json:"groupname" validate:"required"`
+	Usernames []string `json:"usernames" validate:"required"`
+}

app/model/message.go

@@ -0,0 +1,126 @@
+package model
+
+import (
+	"net/http"
+	"time"
+
+	c "github.com/aorticweb/msg-app/app/common"
+	"github.com/aorticweb/msg-app/app/crud"
+	"gorm.io/gorm"
+)
+
+type ReplyMessage struct {
+	Sender  string `json:"sender" validate:"required"`
+	Subject string `json:"subject" validate:"required"`
+	Body    string `json:"body" validate:"required"`
+}
+
+func (rm *ReplyMessage) ValidateSender(db *gorm.DB) (*int64, *c.APIResponse) {
+	sender, exist, err := crud.FindUser(db, rm.Sender)
+	if err != nil {
+		return nil, c.NewBadResponse(http.StatusInternalServerError, "", c.WrapError("failed to query users", err))
+	}
+	if !exist {
+		return nil, c.NewBadResponse(http.StatusNotFound, "user with given username does not exist", nil)
+	}
+	return &sender.ID, nil
+}
+
+func (rm *ReplyMessage) Validate(db *gorm.DB, reID int64) (*crud.Message, *c.APIResponse) {
+	msg := crud.Message{
+		Subject: rm.Subject,
+		Body:    rm.Body,
+		SentAt:  time.Now().UTC(),
+	}
+	senderID, badResp := rm.ValidateSender(db)
+	if badResp != nil {
+		return nil, badResp
+	}
+	msg.SenderID = senderID
+	reMessage, exist, err := crud.GetMessage(db, reID)
+	if err != nil {
+		return nil, c.NewBadResponse(http.StatusInternalServerError, "", c.WrapError("failed to query message", err))
+	}
+	if !exist {
+		return nil, c.NewBadResponse(http.StatusNotFound, "message with given id does not exist", nil)
+	}
+	msg.REID = &reMessage.ID
+	return &msg, nil
+}
+
+type ComposedMessage struct {
+	ReplyMessage
+	Recipient map[string]string `json:"recipient"` // Either crud.User or crud.Group
+}
+
+func (m *ComposedMessage) Validate(db *gorm.DB) (*crud.Message, *c.APIResponse) {
+	msg := crud.Message{
+		Subject: m.Subject,
+		Body:    m.Body,
+		SentAt:  time.Now().UTC(),
+	}
+	username, usernameFound := m.Recipient["username"]
+	groupname, groupnameFound := m.Recipient["groupname"]
+	if usernameFound && groupnameFound {
+		return nil, c.NewBadResponse(http.StatusBadRequest, "invalid request", nil)
+	}
+	senderID, badResp := m.ValidateSender(db)
+	if badResp != nil {
+		return nil, badResp
+	}
+	msg.SenderID = senderID
+	if usernameFound {
+		user, exist, err := crud.FindUser(db, username)
+		if err != nil {
+			return nil, c.NewBadResponse(http.StatusInternalServerError, "", c.WrapError("failed to query user", err))
+		}
+		if !exist {
+			return nil, c.NewBadResponse(http.StatusNotFound, "recipient user with given username does not exist", nil)
+		}
+		msg.RecipientID = &user.ID
+		return &msg, nil
+	}
+	if groupnameFound {
+		group, exist, err := crud.FindGroup(db, groupname)
+		if err != nil {
+			return nil, c.NewBadResponse(http.StatusInternalServerError, "", c.WrapError("failed to query group", err))
+		}
+		if !exist {
+			return nil, c.NewBadResponse(http.StatusNotFound, "recipient group with given groupname does not exist", nil)
+		}
+		msg.GroupID = &group.ID
+		return &msg, nil
+	}
+	return nil, c.NewBadResponse(http.StatusBadRequest, "invalid request", nil)
+}
+
+type Message struct {
+	ComposedMessage
+	ID     int64     `json:"id" validate:"required"`
+	RE     int64     `json:"re"`
+	SentAt time.Time `json:"sent_at" validate:"required"`
+}
+
+func ResponseMessageFromDBMessage(m *crud.Message) *Message {
+	rv := Message{
+		ID: m.ID,
+		RE: *m.REID,
+		ComposedMessage: ComposedMessage{
+			ReplyMessage: ReplyMessage{
+				Subject: m.Subject,
+				Body:    m.Body,
+				Sender:  m.Sender.Username,
+			},
+			Recipient: make(map[string]string),
+		},
+		SentAt: m.SentAt,
+	}
+	// Purposefully not raising an error here if
+	// both user and group are missing because of db constraint
+	if m.Group != nil {
+		rv.Recipient["groupname"] = m.Group.Groupname
+	} else if m.Recipient != nil {
+		rv.Recipient["username"] = m.Recipient.Username
+	}
+	return &rv
+}

db/migrations/20220125181413_init.sql

@@ -11,15 +11,17 @@ create table if not exists user_group (
     id SERIAL primary key,
     user_id int references public.user(id) not null,
     group_id int references public.group(id) not null,
-    CONSTRAINT unique_user_group UNIQUE (user_id, group_id)
+    CONSTRAINT user_group_unique_user_group UNIQUE (user_id, group_id)
 );
 create table if not exists message (
     id SERIAL primary key,
     re_id int references message(id),
     sender_id int references public.user(id) not null,
-    recipient_id int references public.user(id) not null,
+    recipient_id int references public.user(id) null,
+    group_id int references public.group(id) null,
     subject text,
     body text,
-    sent_at timestamp without time zone not null
+    sent_at timestamp without time zone not null,
+    CHECK (recipient_id is not null OR group_id is not null)
 )
 -- migrate:down

go.mod

@@ -4,6 +4,7 @@ go 1.17
 
 require (
 	github.com/davecgh/go-spew v1.1.1 // indirect
+	github.com/fatih/structs v1.1.0 // indirect
 	github.com/go-playground/locales v0.14.0 // indirect
 	github.com/go-playground/universal-translator v0.18.0 // indirect
 	github.com/go-playground/validator/v10 v10.10.0 // indirect

go.sum

@@ -8,6 +8,8 @@ github.com/creack/pty v1.1.9/go.mod h1:oKZEueFk5CKHvIhNR5MUki03XCEU+Q6VDXinZuGJ3
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/fatih/structs v1.1.0 h1:Q7juDM0QtcnhCpeyLGQKyg4TOIghuNXrkL32pHAUMxo=
+github.com/fatih/structs v1.1.0/go.mod h1:9NiDSp5zOcgEDl+j00MP/WkGVPOlPRLejGD8Ga6PJ7M=
 github.com/go-kit/log v0.1.0/go.mod h1:zbhenjAZHb184qTLMA9ZjW7ThYL0H2mk7Q6pNt4vbaY=
 github.com/go-logfmt/logfmt v0.5.0/go.mod h1:wCYkCAKZfumFQihp8CzCvQ3paCTfi41vtzG1KdI/P7A=
 github.com/go-playground/assert/v2 v2.0.1/go.mod h1:VDjEfimB/XKnb+ZQfWdccd7VUvScMdVu0Titje2rxJ4=