Add finnhub static JSON provider

accountProviders.go

@@ -3,6 +3,7 @@ package main
 import (
 	"deadbeef.codes/steven/ynab-portfolio-monitor/bitcoin"
 	"deadbeef.codes/steven/ynab-portfolio-monitor/questrade"
+	"deadbeef.codes/steven/ynab-portfolio-monitor/staticjsonFinnhub"
 )
 
 // AccountProvider is the base set of requirements to be implemented for any integration
@@ -17,4 +18,5 @@ type AccountProvider interface {
 var allProviders []AccountProvider = []AccountProvider{
 	&questrade.Provider{},
 	&bitcoin.Provider{},
+	&staticjsonFinnhub.Provider{},
 }

staticjsonFinnhub/README.md

@@ -0,0 +1,23 @@
+# Static JSON Finnhub Provider
+
+If you just want to provide a static JSON file as input containing symbols and quantities owned, this provider will use finnhub for pricing quotes for the symbols provided.
+
+### Example data/staticjsonFinnhub-data.json
+
+You can define many to many relationships, multiple YNAB accounts containing multiple types of securities using json arrays.
+
+```json
+{
+    "accounts":[
+        {
+            "ynabAccountId":"d54da05a-cs20-4654-bcff-9ce36f43225d",
+            "securities":[
+                {
+                    "symbol":"SPY",
+                    "quantity":420
+                }
+            ]
+        }
+    ]
+}
+```

staticjsonFinnhub/client.go

@@ -0,0 +1,84 @@
+package staticjsonFinnhub
+
+import (
+	"encoding/json"
+	"fmt"
+	"io"
+	"net/http"
+	"net/url"
+	"time"
+)
+
+const apiBaseURL = "https://finnhub.io/api/v1/"
+
+// A client is the structure that will be used to consume the API
+// endpoints. It holds the login credentials, http client/transport,
+// rate limit information, and the login session timer.
+type client struct {
+	apiToken   string
+	httpClient *http.Client
+	transport  *http.Transport
+}
+
+// Send an HTTP GET request, and return the processed response
+func (c *client) get(endpoint string, out interface{}, query url.Values) error {
+	req, err := http.NewRequest("GET", apiBaseURL+endpoint+"?"+query.Encode(), nil)
+	if err != nil {
+		return err
+	}
+	req.Header.Add("X-Finnhub-Token", c.apiToken)
+
+	res, err := c.httpClient.Do(req)
+	if err != nil {
+		return fmt.Errorf("http get request failed: %v", err)
+	}
+
+	err = c.processResponse(res, out)
+	if err != nil {
+		return err
+	}
+	return nil
+}
+
+// processResponse takes the body of an HTTP response, and either returns
+// the error code, or unmarshalls the JSON response, extracts
+// rate limit info, and places it into the object
+// output parameter. This function closes the response body after reading it.
+func (c *client) processResponse(res *http.Response, out interface{}) error {
+	body, err := io.ReadAll(res.Body)
+	res.Body.Close()
+	if err != nil {
+		return err
+	}
+
+	if res.StatusCode != 200 {
+		return fmt.Errorf("got http response status '%d' but expected 200", res.StatusCode)
+	}
+
+	err = json.Unmarshal(body, out)
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+
+// newClient is the factory function for clients - takes an API token
+func newClient(apiToken string) (*client, error) {
+	transport := &http.Transport{
+		ResponseHeaderTimeout: 5 * time.Second,
+	}
+
+	httpClient := &http.Client{
+		Transport: transport,
+	}
+
+	// Create a new client
+	c := &client{
+		apiToken:   apiToken,
+		httpClient: httpClient,
+		transport:  transport,
+	}
+
+	return c, nil
+}

staticjsonFinnhub/providerImpl.go

@@ -0,0 +1,100 @@
+package staticjsonFinnhub
+
+import (
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io"
+	"os"
+)
+
+type security struct {
+	Symbol   string `json:"symbol"`
+	Quantity int    `json:"quantity"`
+}
+
+type account struct {
+	YnabAccountID string     `json:"ynabAccountId"`
+	Securities    []security `json:"securities"`
+}
+
+type inputData struct {
+	Accounts []account `json:"accounts"`
+}
+
+type Provider struct {
+	data   *inputData // Data stored on disk and loaded when program starts
+	client *client    // HTTP client for interacting with Finnhub API
+}
+
+func (p *Provider) Name() string {
+	return "Static JSON - Finnhub"
+}
+
+// Configures the provider for usage via environment variables and inputData
+// If an error is returned, the provider will not be used
+func (p *Provider) Configure() error {
+	var err error
+
+	// Load input data from disk
+	p.data, err = loadInputData()
+	if err != nil {
+		return err
+	}
+
+	b, _ := json.Marshal(p.data)
+	fmt.Println(string(b))
+
+	apiKey := os.Getenv("staticjson_finnhub_key")
+	if apiKey == "" {
+		return fmt.Errorf("this account provider is not configured: missing staticjson_finnhub_key environment variable")
+	}
+
+	p.client, err = newClient(apiKey)
+	if err != nil {
+		return fmt.Errorf("failed to create new client: %v", err)
+	}
+
+	return nil
+}
+
+// Returns slices of account balances and mapped YNAB account IDs, along with an error
+func (p *Provider) GetBalances() ([]int, []string, error) {
+	balances := make([]int, 0)
+	ynabAccountIDs := make([]string, 0)
+	for i := range p.data.Accounts {
+		balance := 0
+		for j := range p.data.Accounts[i].Securities {
+			price, err := p.client.getQuote(p.data.Accounts[i].Securities[j].Symbol)
+			if err != nil {
+				return balances, ynabAccountIDs, fmt.Errorf("failed to get quote for security with symbol '%s': %v", p.data.Accounts[i].Securities[j].Symbol, err)
+			}
+			balance += price * p.data.Accounts[i].Securities[j].Quantity
+		}
+		balances = append(balances, balance)
+		ynabAccountIDs = append(ynabAccountIDs, p.data.Accounts[i].YnabAccountID)
+	}
+	return balances, ynabAccountIDs, nil
+}
+
+// Load input data from disk
+func loadInputData() (*inputData, error) {
+	data := &inputData{}
+
+	f, err := os.Open("data/staticjson-data.json")
+	if errors.Is(err, os.ErrNotExist) {
+		return nil, fmt.Errorf("this account provider is not configured: missing data/staticjson-data.json")
+	}
+	defer f.Close()
+	b, err := io.ReadAll(f)
+	if err != nil {
+		return nil, fmt.Errorf("failed to read file data/staticjson-data.json: %v", err)
+	}
+
+	err = json.Unmarshal(b, data)
+	if err != nil {
+		return nil, fmt.Errorf("failed to unmarshal data/staticjson-data.json to inputData struct: %v", err)
+	}
+
+	return data, nil
+}

staticjsonFinnhub/quote.go

@@ -0,0 +1,26 @@
+package staticjsonFinnhub
+
+import (
+	"fmt"
+	"net/url"
+)
+
+type quote struct {
+	C  float64 `json:"c"`  // Current price
+	H  float64 `json:"h"`  // High price of the day
+	L  float64 `json:"l"`  // Low price of the day
+	O  float64 `json:"O"`  // Open price of the day
+	Pc float64 `json:"pc"` // Previous close price
+	T  int     `json:"t"`  // ?
+}
+
+func (c client) getQuote(symbol string) (int, error) {
+	quoteResponse := &quote{}
+	query := url.Values{}
+	query.Add("symbol", symbol)
+	err := c.get("/quote", quoteResponse, query)
+	if err != nil {
+		return 0, fmt.Errorf("http get request error: %v", err)
+	}
+	return int(quoteResponse.C * 1000), nil
+}