feat: initial FRED API Proxy project

- Go web server using Gin framework
- Proxy FRED economic data API
- Support series, observations, search, releases endpoints
This commit is contained in:
2026-04-01 06:48:29 +00:00
commit 96711ffb35
10 changed files with 755 additions and 0 deletions

291
handlers/fred.go Normal file
View File

@@ -0,0 +1,291 @@
package handlers
import (
"encoding/json"
"fmt"
"io"
"net/http"
"net/url"
"strconv"
"strings"
"fred-api/config"
"fred-api/models"
"github.com/gin-gonic/gin"
)
type FREDHandler struct {
baseURL string
apiKey string
}
func NewFREDHandler(cfg *config.Config) *FREDHandler {
return &FREDHandler{
baseURL: cfg.FREDBaseURL,
apiKey: cfg.FREDAPIKey,
}
}
func (h *FREDHandler) buildURL(endpoint string, params map[string]string) string {
u, _ := url.Parse(h.baseURL + endpoint)
query := u.Query()
query.Set("api_key", h.apiKey)
query.Set("file_type", "json")
for k, v := range params {
if v != "" {
query.Set(k, v)
}
}
u.RawQuery = query.Encode()
return u.String()
}
func (h *FREDHandler) fetchData(url string, target interface{}) error {
resp, err := http.Get(url)
if err != nil {
return err
}
defer resp.Body.Close()
body, err := io.ReadAll(resp.Body)
if err != nil {
return err
}
if resp.StatusCode != http.StatusOK {
var errResp models.ErrorResponse
json.Unmarshal(body, &errResp)
return fmt.Errorf("API error: %s - %s", errResp.ErrorCode, errResp.ErrorMessage)
}
return json.Unmarshal(body, target)
}
func (h *FREDHandler) GetSeries(c *gin.Context) {
seriesID := c.Query("series_id")
if seriesID == "" {
c.JSON(http.StatusBadRequest, models.ErrorResponse{
ErrorCode: "BadRequest",
ErrorMessage: "series_id is required",
})
return
}
params := map[string]string{
"series_id": seriesID,
}
if realtimeStart := c.Query("realtime_start"); realtimeStart != "" {
params["realtime_start"] = realtimeStart
}
if realtimeEnd := c.Query("realtime_end"); realtimeEnd != "" {
params["realtime_end"] = realtimeEnd
}
url := h.buildURL("/series", params)
var response models.SeriesListResponse
if err := h.fetchData(url, &response); err != nil {
c.JSON(http.StatusInternalServerError, models.ErrorResponse{
ErrorCode: "InternalError",
ErrorMessage: err.Error(),
})
return
}
c.JSON(http.StatusOK, response)
}
func (h *FREDHandler) GetObservations(c *gin.Context) {
seriesID := c.Query("series_id")
if seriesID == "" {
c.JSON(http.StatusBadRequest, models.ErrorResponse{
ErrorCode: "BadRequest",
ErrorMessage: "series_id is required",
})
return
}
params := map[string]string{
"series_id": seriesID,
}
optionalParams := []string{
"realtime_start", "realtime_end", "limit", "offset", "sort_order",
"observation_start", "observation_end", "units", "frequency",
"aggregation_method", "output_type", "vintage_dates",
}
for _, param := range optionalParams {
if v := c.Query(param); v != "" {
params[param] = v
}
}
url := h.buildURL("/series/observations", params)
var response models.ObservationsResponse
if err := h.fetchData(url, &response); err != nil {
c.JSON(http.StatusInternalServerError, models.ErrorResponse{
ErrorCode: "InternalError",
ErrorMessage: err.Error(),
})
return
}
c.JSON(http.StatusOK, response)
}
func (h *FREDHandler) SearchSeries(c *gin.Context) {
searchText := c.Query("search_text")
if searchText == "" {
c.JSON(http.StatusBadRequest, models.ErrorResponse{
ErrorCode: "BadRequest",
ErrorMessage: "search_text is required",
})
return
}
params := map[string]string{
"search_text": searchText,
}
optionalParams := []string{
"realtime_start", "realtime_end", "limit", "offset", "sort_order",
"observation_start", "observation_end", "units", "frequency",
"aggregation_method", "output_type",
}
for _, param := range optionalParams {
if v := c.Query(param); v != "" {
params[param] = v
}
}
url := h.buildURL("/series/search", params)
var response models.SearchResponse
if err := h.fetchData(url, &response); err != nil {
c.JSON(http.StatusInternalServerError, models.ErrorResponse{
ErrorCode: "InternalServerError",
ErrorMessage: err.Error(),
})
return
}
c.JSON(http.StatusOK, response)
}
func (h *FREDHandler) GetReleases(c *gin.Context) {
params := map[string]string{}
optionalParams := []string{
"realtime_start", "realtime_end", "limit", "offset", "sort_order",
}
for _, param := range optionalParams {
if v := c.Query(param); v != "" {
params[param] = v
}
}
url := h.buildURL("/releases", params)
var response models.ReleasesResponse
if err := h.fetchData(url, &response); err != nil {
c.JSON(http.StatusInternalServerError, models.ErrorResponse{
ErrorCode: "InternalServerError",
ErrorMessage: err.Error(),
})
return
}
c.JSON(http.StatusOK, response)
}
func (h *FREDHandler) GetReleaseDates(c *gin.Context) {
params := map[string]string{}
optionalParams := []string{
"realtime_start", "realtime_end", "limit", "offset", "sort_order",
"release_id", "date", "start_date", "end_date",
}
for _, param := range optionalParams {
if v := c.Query(param); v != "" {
params[param] = v
}
}
url := h.buildURL("/releases/dates", params)
var response models.ReleaseDatesResponse
if err := h.fetchData(url, &response); err != nil {
c.JSON(http.StatusInternalServerError, models.ErrorResponse{
ErrorCode: "InternalServerError",
ErrorMessage: err.Error(),
})
return
}
c.JSON(http.StatusOK, response)
}
func (h *FREDHandler) GetReleaseSeries(c *gin.Context) {
releaseIDStr := c.Query("release_id")
if releaseIDStr == "" {
c.JSON(http.StatusBadRequest, models.ErrorResponse{
ErrorCode: "BadRequest",
ErrorMessage: "release_id is required",
})
return
}
releaseID, err := strconv.Atoi(releaseIDStr)
if err != nil {
c.JSON(http.StatusBadRequest, models.ErrorResponse{
ErrorCode: "BadRequest",
ErrorMessage: "release_id must be a number",
})
return
}
params := map[string]string{
"release_id": strings.TrimSpace(strings.Replace(strconv.Itoa(releaseID), " ", "", -1)),
}
optionalParams := []string{
"realtime_start", "realtime_end", "limit", "offset", "sort_order",
"observation_start", "observation_end", "units", "frequency",
"aggregation_method", "output_type",
}
for _, param := range optionalParams {
if v := c.Query(param); v != "" {
params[param] = v
}
}
url := h.buildURL("/release/series", params)
var response models.SearchResponse
if err := h.fetchData(url, &response); err != nil {
c.JSON(http.StatusInternalServerError, models.ErrorResponse{
ErrorCode: "InternalServerError",
ErrorMessage: err.Error(),
})
return
}
c.JSON(http.StatusOK, response)
}
func (h *FREDHandler) HealthCheck(c *gin.Context) {
c.JSON(http.StatusOK, gin.H{
"status": "healthy",
"service": "FRED API Proxy",
})
}