Add: get balance request

docs/spec/components/schemas/Balance.yaml

@@ -0,0 +1,16 @@
+allOf:
+  - $ref: '#/components/schemas/TokenKey'
+  - type: object
+    required:
+      - attributes
+    properties:
+      attributes:
+        type: object
+        required:
+          - amount
+        properties:
+          amount:
+            type: integer
+            format: "*big.Int"
+            description: Amount of the tokens on the user address
+            example: "123"

docs/spec/components/schemas/TokenKey.yaml

@@ -0,0 +1,10 @@
+type: object
+required:
+  - id
+  - type
+properties:
+  id:
+    type: string
+  type:
+    type: string
+    enum: [ token ]

docs/spec/paths/token@balance.yaml

@@ -0,0 +1,28 @@
+get:
+  tags:
+    - Tokens
+  summary: Get Balance
+  description: Get token's balance by the given user address
+  operationId: GetBalance
+  parameters:
+    - in: query
+      name: address
+      required: true
+      schema:
+        type: string
+        format: common.Address
+  responses:
+    200:
+      content:
+        application/vnd.api+json:
+          schema:
+            type: object
+            required:
+              - data
+            properties:
+              data:
+                $ref: '#/components/schemas/Balance'
+    400:
+      $ref: '#/components/responses/invalidParameter'
+    500:
+      $ref: '#/components/responses/internalError'

go.mod

@@ -123,6 +123,7 @@ require (
 	github.com/tklauser/numcpus v0.6.1 // indirect
 	gitlab.com/distributed_lab/figure v2.1.2+incompatible // indirect
 	gitlab.com/distributed_lab/lorem v0.2.1 // indirect
+	gitlab.com/distributed_lab/urlval v3.0.0+incompatible // indirect
 	go.etcd.io/bbolt v1.3.7 // indirect
 	go.uber.org/multierr v1.11.0 // indirect
 	golang.org/x/crypto v0.22.0 // indirect

go.sum

@@ -2298,6 +2298,8 @@ gitlab.com/distributed_lab/lorem v0.2.1 h1:A1QoiEDRN3vlPrwsXJmPlENanQwu3FxpDl5vE
 gitlab.com/distributed_lab/lorem v0.2.1/go.mod h1:wkzrGoB1L/yUBu56SfoJ/vNiPqiHZcg75AnBkWNcjhQ=
 gitlab.com/distributed_lab/running v1.6.0 h1:O2GQHgYkpNRDbobR11atOCH2rhS1okNKyadiAqi+kQI=
 gitlab.com/distributed_lab/running v1.6.0/go.mod h1:4TnADX84dQjQMRHKIMPCVL0L97rD/Jxv0xDbrN6aKzk=
+gitlab.com/distributed_lab/urlval v3.0.0+incompatible h1:OWU3CcZU+z0BVooufOSQFO9biDfsjM3e7YYauC278HU=
+gitlab.com/distributed_lab/urlval v3.0.0+incompatible/go.mod h1:cKnUlnZCHUuke/l95YLvW5JoGC2yn53HVgF9rt1WiIg=
 go.etcd.io/bbolt v1.3.7 h1:j+zJOnnEjF/kyHlDDgGnVL/AIqIJPq8UoB2GSNfkUfQ=
 go.etcd.io/bbolt v1.3.7/go.mod h1:N9Mkw9X8x5fupy0IKsmuqVtoGDyxsaDlbk4Rd05IAQw=
 go.etcd.io/etcd/api/v3 v3.5.10/go.mod h1:TidfmT4Uycad3NM/o25fG3J07odo4GBB9hoxaodFCtI=

internal/service/api/handlers/get_balance.go

@@ -0,0 +1,30 @@
+package handlers
+
+import (
+	"net/http"
+
+	"github.com/ethereum/go-ethereum/accounts/abi/bind"
+	"github.com/rarimo/evm-airdrop-svc/internal/service/api"
+	"github.com/rarimo/evm-airdrop-svc/internal/service/api/models"
+	"github.com/rarimo/evm-airdrop-svc/internal/service/api/requests"
+	"gitlab.com/distributed_lab/ape"
+	"gitlab.com/distributed_lab/ape/problems"
+)
+
+func GetBalance(w http.ResponseWriter, r *http.Request) {
+	req, err := requests.NewGetBalanceRequest(r)
+	if err != nil {
+		api.Log(r).WithError(err).Error("failed to parse request")
+		ape.RenderErr(w, problems.BadRequest(err)...)
+		return
+	}
+
+	balance, err := api.ERC20Permit(r).BalanceOf(&bind.CallOpts{}, req.Address)
+	if err != nil {
+		api.Log(r).WithError(err).Error("failed to get user balance")
+		ape.RenderErr(w, problems.InternalError())
+		return
+	}
+
+	ape.Render(w, models.NewBalanceResponse(req.Address.String(), balance))
+}

internal/service/api/models/token.go

@@ -0,0 +1,21 @@
+package models
+
+import (
+	"math/big"
+
+	"github.com/rarimo/evm-airdrop-svc/resources"
+)
+
+func NewBalanceResponse(addr string, amount *big.Int) resources.BalanceResponse {
+	return resources.BalanceResponse{
+		Data: resources.Balance{
+			Key: resources.Key{
+				ID:   addr,
+				Type: resources.TOKEN,
+			},
+			Attributes: resources.BalanceAttributes{
+				Amount: amount,
+			},
+		},
+	}
+}

internal/service/api/requests/get_balance.go

@@ -0,0 +1,32 @@
+package requests
+
+import (
+	"net/http"
+
+	"github.com/ethereum/go-ethereum/common"
+	validation "github.com/go-ozzo/ozzo-validation/v4"
+	"gitlab.com/distributed_lab/logan/v3/errors"
+	"gitlab.com/distributed_lab/urlval"
+)
+
+type GetUserBalanceRequest struct {
+	Address common.Address `url:"address"`
+}
+
+func NewGetBalanceRequest(r *http.Request) (GetUserBalanceRequest, error) {
+	var req GetUserBalanceRequest
+
+	if err := urlval.Decode(r.URL.Query(), &req); err != nil {
+		return req, validation.Errors{
+			"query": errors.Wrap(err, "failed to decode url"),
+		}.Filter()
+	}
+
+	return req, req.validate()
+}
+
+func (r *GetUserBalanceRequest) validate() error {
+	return validation.Errors{
+		"/address": validation.Validate(r.Address, validation.Required),
+	}.Filter()
+}

internal/service/router.go

@@ -55,6 +55,10 @@ func Run(ctx context.Context, cfg *config.Config) {
 
 			r.Post("/permit-hash", handlers.BuildPermitHash)
 		})
+
+		r.Route("/token", func(r chi.Router) {
+			r.Get("/balance", handlers.GetBalance)
+		})
 	})
 
 	cfg.Log().Info("Service started")

resources/model_balance.go

@@ -0,0 +1,43 @@
+/*
+ * GENERATED. Do not modify. Your changes might be overwritten!
+ */
+
+package resources
+
+import "encoding/json"
+
+type Balance struct {
+	Key
+	Attributes BalanceAttributes `json:"attributes"`
+}
+type BalanceResponse struct {
+	Data     Balance  `json:"data"`
+	Included Included `json:"included"`
+}
+
+type BalanceListResponse struct {
+	Data     []Balance       `json:"data"`
+	Included Included        `json:"included"`
+	Links    *Links          `json:"links"`
+	Meta     json.RawMessage `json:"meta,omitempty"`
+}
+
+func (r *BalanceListResponse) PutMeta(v interface{}) (err error) {
+	r.Meta, err = json.Marshal(v)
+	return err
+}
+
+func (r *BalanceListResponse) GetMeta(out interface{}) error {
+	return json.Unmarshal(r.Meta, out)
+}
+
+// MustBalance - returns Balance from include collection.
+// if entry with specified key does not exist - returns nil
+// if entry with specified key exists but type or ID mismatches - panics
+func (c *Included) MustBalance(key Key) *Balance {
+	var balance Balance
+	if c.tryFindEntry(key, &balance) {
+		return &balance
+	}
+	return nil
+}

resources/model_balance_attributes.go

@@ -0,0 +1,12 @@
+/*
+ * GENERATED. Do not modify. Your changes might be overwritten!
+ */
+
+package resources
+
+import "math/big"
+
+type BalanceAttributes struct {
+	// Amount of the tokens on the user address
+	Amount *big.Int `json:"amount"`
+}

resources/model_resource_type.go

@@ -10,5 +10,6 @@ type ResourceType string
 const (
 	AIRDROP        ResourceType = "airdrop"
 	CREATE_AIRDROP ResourceType = "create_airdrop"
+	TOKEN          ResourceType = "token"
 	TRANSFER_ERC20 ResourceType = "transfer_erc20"
 )