wgoodall01/wikipath

package main

import (
    "encoding/json"
    wp "github.com/wgoodall01/wikipath/wp"
    "log"
    "net/http"
    "time"
)

type PathResponse struct {
    From     string   `json:"from"`     // Starting article
    To       string   `json:"to"`       // Ending article
    Path     []string `json:"path"`     // Path between articles.
    Duration float64  `json:"duration"` // Duration of query.
    Touched  int      `json:"touched"`  // How many articles touched.
}

type QueryHandler struct {
    ind *wp.Index
}

func NewQueryHandler(ind *wp.Index) *QueryHandler {
    return &QueryHandler{
        ind: ind,
    }
}

func (qh *QueryHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
    query := r.URL.Query()
    fromName := query.Get("from")
    toName := query.Get("to")

    if fromName == "" || toName == "" {
        NewHttpError(http.StatusBadRequest, "Both 'from' and 'to' query parameters required").Send(w)
        return
    }

    // Get articles
    fromItem := qh.ind.Get(fromName)
    toItem := qh.ind.Get(toName)

    if fromItem == nil {
        NewHttpError(http.StatusNotFound, "Could not find 'from' article.").Send(w)
        return
    }
    if toItem == nil {
        NewHttpError(http.StatusNotFound, "Could not find 'to' article").Send(w)
        return
    }

    // Find path.
    tStart := time.Now()
    path, touched := qh.ind.FindPath(fromItem, toItem, MAX_DEPTH)
    duration := time.Since(tStart)

    if path == nil {
        NewHttpError(http.StatusNotFound, "Could not find valid path").Send(w)
        return
    }

    titles := path.ToStringSlice()
    resp := PathResponse{
        From:     fromName,
        To:       toName,
        Path:     titles,
        Duration: duration.Seconds(),
        Touched:  touched,
    }

    respBytes, respErr := json.MarshalIndent(resp, "", "  ")
    if respErr != nil {
        panic(respErr)
    }

    w.Write(respBytes)
    log.Printf("'%s' -> '%s' in %0.2f", fromName, toName, duration.Seconds())
}