merp/merp.go

package merp

import "encoding/json"
import "net/http"
import "time"

import "github.com/astaxie/beego/orm"
import "github.com/gin-gonic/gin"
import "github.com/google/uuid"
import "github.com/rs/zerolog/log"
import "github.com/sneak/merp/models"

const MAX_MERPS_TO_RETURN = 50
const LONGPOLL_TIMEOUT_SECS = 60

func decodeJSON(in []byte) (interface{}, error) {
	var out interface{}
	err := json.Unmarshal(in, &out)
	if err != nil {
		log.Error().Msg("error decoding json")
		return nil, err
	}
	return out, nil
}

func (ms *Server) listenForMerps() gin.HandlerFunc {
	// /listen/for/merps/from/my-thing-name
	return func(c *gin.Context) {
		thing := c.Param("thing")
		if thing != "" {
			if thingRegex.MatchString(thing) == false {
				c.JSON(http.StatusPreconditionFailed, gin.H{
					"this":    "failed",
					"status":  http.StatusPreconditionFailed,
					"because": "invalid thing format, try [a-zA-Z0-9-_.]",
				})
				return
			}
		}

		el := NewEventListener(MerpTopic(thing))

		timeout := time.After(LONGPOLL_TIMEOUT_SECS * time.Second)
		// Keep trying until we're timed out or got a result or got an error
		for {
			select {
			case <-c.Done():
				// unregister listener and close conn FIXME
			case <-timeout:
				// unregister listener and close conn FIXME
			case newMerpJSON := <-el.NewMerpJSONChannel:
				log.Info().Msg(newMerpJSON)
				// send them some json FIXME
			}
		}
	}
}

func (ms *Server) getLatestMerps() gin.HandlerFunc {
	return func(c *gin.Context) {
		thing := c.Param("thing")

		if thing != "" {
			if thingRegex.MatchString(thing) == false {
				c.JSON(http.StatusPreconditionFailed, gin.H{
					"this":    "failed",
					"status":  http.StatusPreconditionFailed,
					"because": "invalid thing format, try [a-zA-Z0-9-_]",
				})
				return
			}
		}

		var qs orm.QuerySeter
		if thing == "" {
			qs = ms.db.QueryTable("merp").OrderBy("-created").Limit(MAX_MERPS_TO_RETURN)
		} else {
			qs = ms.db.QueryTable("merp").Filter("thing", thing).OrderBy("-created").Limit(MAX_MERPS_TO_RETURN)
		}

		var merps []*models.Merp
		qs.All(&merps)

		output := make([]map[string]interface{}, 0)
		for _, merp := range merps {
			outelem := make(map[string]interface{})
			outelem["thing"] = merp.Thing
			outjs, err := decodeJSON([]byte(merp.Content))
			if err != nil {
				outelem["content"] = gin.H{}
			} else {
				outelem["content"] = outjs
			}
			outelem["created"] = merp.Created
			output = append(output, outelem)
		}

		c.JSON(http.StatusOK, gin.H{
			"this": "succeeded",
			"by":   "getting",
			"the":  "merps",
			"with": output,
		})
	}
}

func (ms *Server) handleNewMerp() gin.HandlerFunc {
	return func(c *gin.Context) {
		// request time
		thing := c.Param("thing")
		if thingRegex.MatchString(thing) == false {
			c.JSON(http.StatusPreconditionFailed, gin.H{
				"this":    "failed",
				"status":  http.StatusPreconditionFailed,
				"because": "invalid thing format, try a-zA-Z0-9-_",
			})
			return
		}

		// FIXME rate limit this a bit on thing+clientip+json to cut down on
		// repeated messages
		content := make(map[string]interface{})
		respContent := gin.H{}
		// FIXME support POST data as well

		for k, v := range c.Request.URL.Query() {
			content[k] = v[0]
			respContent[k] = v[0]
		}

		u := uuid.New()
		at := time.Now().UTC()
		atString := at.Format(time.RFC3339)

		serialized, jsonerr := json.MarshalIndent(content, "", "    ")

		if jsonerr != nil {
			c.JSON(
				http.StatusPreconditionFailed,
				gin.H{
					"this":    "failed",
					"status":  http.StatusPreconditionFailed,
					"because": jsonerr.Error(),
				},
			)
			return
		}

		merp := models.Merp{
			Created: at,
			Thing:   thing,
			Content: string(serialized),
			UUID:    u.String(),
		}

		_, err := ms.db.Insert(&merp)

		if err != nil {
			c.JSON(
				http.StatusPreconditionFailed,
				gin.H{
					"this":    "failed",
					"status":  http.StatusPreconditionFailed,
					"because": err.Error(),
				},
			)
			return
		}

		c.JSON(http.StatusOK, gin.H{
			"this": "succeeded",
			"by":   "merping",
			"the":  "merp",
			"with": gin.H{
				"thing":       thing,
				"created":     atString,
				"content":     respContent,
				"transaction": u.String(),
			},
		})
	}
}