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main.go
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/
main.go
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// Copyright 2014 Kevin Bowrin All rights reserved.
// Use of this source code is governed by the MIT
// license that can be found in the LICENSE file.
/*
This package implements a proxy for III's Sierra API.
It handles authentication and improves access to more commonly used data,
like item status.
*/
package main
import (
"crypto/tls"
"encoding/json"
"errors"
"flag"
"fmt"
l "github.com/cudevmaxwell/tyro/loglevel"
"github.com/cudevmaxwell/tyro/sierraapi"
"github.com/cudevmaxwell/tyro/tokenstore"
"log"
"net/http"
"net/http/httputil"
"net/url"
"os"
"path"
"sort"
"strconv"
"strings"
"time"
)
const (
//The prefix for all the curator environment variables
EnvPrefix string = "TYRO_"
//The default address to serve from
DefaultAddress string = ":8877"
//Will we allow raw mode access?
DefaultRawAccess bool = false
//The default Access-Control-Allow-Origin header (CORS)
DefaultACAOHeader string = "*"
)
var (
address = flag.String("address", DefaultAddress, "Address for the server to bind on.")
apiURL = flag.String("url", sierraapi.DefaultURL, "API url.")
certFile = flag.String("certfile", "", "Certificate file location.")
keyFile = flag.String("keyfile", "", "Private key file location.")
clientKey = flag.String("key", "", "Client Key")
clientSecret = flag.String("secret", "", "Client Secret")
headerACAO = flag.String("acaoheader", DefaultACAOHeader, "Access-Control-Allow-Origin Header for CORS. Multiple origins separated by ;")
raw = flag.Bool("raw", DefaultRawAccess, "Allow access to the raw Sierra API under /raw/")
newLimit = flag.Int("newlimit", 16, "The number of items to serve from the /new endpoint.")
logFileLocation = flag.String("logfile", l.DefaultLogFileLocation, "Log file. By default, log messages will be printed to stdout.")
logMaxSize = flag.Int("logmaxsize", l.DefaultLogMaxSize, "The maximum size of log files before they are rotated, in megabytes.")
logMaxBackups = flag.Int("logmaxbackups", l.DefaultLogMaxBackups, "The maximum number of old log files to keep.")
logMaxAge = flag.Int("logmaxage", l.DefaultLogMaxAge, "The maximum number of days to retain old log files, in days.")
logLevel = flag.String("loglevel", "warn", "The maximum log level which will be logged. error < warn < info < debug < trace. For example, trace will log everything, info will log info, warn, and error.")
tokenStore = tokenstore.NewTokenStore()
)
func init() {
flag.Usage = func() {
fmt.Fprint(os.Stderr, "Tyro: A helper for Sierra APIs\nVersion 0.7.8\n\n")
flag.PrintDefaults()
fmt.Fprintln(os.Stderr, " The possible environment variables:")
flag.VisitAll(func(f *flag.Flag) {
uppercaseName := strings.ToUpper(f.Name)
fmt.Fprintf(os.Stderr, " %v%v\n", EnvPrefix, uppercaseName)
})
fmt.Fprintln(os.Stderr, "If a certificate file is provided, Tyro will attempt to use HTTPS.")
fmt.Fprintln(os.Stderr, "The Access-Control-Allow-Origin header for CORS is only set for the /status/bib/[bibID], /status/item/[itemID] and /new endpoints.")
}
}
func main() {
flag.Parse()
l.Set(l.ParseLogLevel(*logLevel))
overrideUnsetFlagsFromEnvironmentVariables()
l.SetupLumberjack(
*logFileLocation,
*logMaxSize,
*logMaxBackups,
*logMaxAge)
l.Log("Starting Tyro", l.InfoMessage)
l.Log("Serving on address: "+*address, l.InfoMessage)
l.Log("Using Client Key: "+*clientKey, l.InfoMessage)
l.Log("Using Client Secret: "+*clientSecret, l.InfoMessage)
l.Log("Connecting to API URL: "+*apiURL, l.InfoMessage)
l.Log("Using ACAO header: "+*headerACAO, l.InfoMessage)
l.Log(fmt.Sprintf("Allowing access to raw Sierra API: %v", *raw), l.InfoMessage)
if *clientKey == "" {
log.Fatal("FATAL: A client key is required to authenticate against the Sierra API.")
} else if *clientSecret == "" {
log.Fatal("FATAL: A client secret is required to authenticate against the Sierra API.")
}
if *headerACAO == "*" {
l.Log("Using \"*\" for \"Access-Control-Allow-Origin\" header. API will be public!", l.WarnMessage)
}
if *certFile != "" {
l.Log("Going to try to serve through HTTPS", l.InfoMessage)
l.Log("Using Certificate File: "+*certFile, l.InfoMessage)
l.Log("Using Private Key File: "+*keyFile, l.InfoMessage)
}
parsedURL, err := parseURLandJoinToPath(*apiURL, sierraapi.TokenRequestEndpoint)
if err != nil {
log.Fatal("FATAL: Unable to parse API URL.")
}
tokenStore.Refresher(parsedURL.String(), *clientKey, *clientSecret)
defer close(tokenStore.Refresh)
http.HandleFunc("/", homeHandler)
http.HandleFunc("/status/", statusHandler)
http.HandleFunc("/status/item/", statusItemHandler)
http.HandleFunc("/status/bib/", statusBibHandler)
http.HandleFunc("/new", newBibsHandler)
if *raw {
l.Log("Allowing access to raw Sierra API.", l.WarnMessage)
rawProxy := httputil.NewSingleHostReverseProxy(&url.URL{})
rawProxy.Director = rawRewriter
http.Handle("/raw/", rawProxy)
}
if *certFile == "" {
log.Fatalf("FATAL: %v", http.ListenAndServe(*address, nil))
} else {
//Remove SSL 3.0 compatibility for POODLE exploit mitigation
config := &tls.Config{MinVersion: tls.VersionTLS10}
server := &http.Server{Addr: *address, Handler: nil, TLSConfig: config}
log.Fatalf("FATAL: %v", server.ListenAndServeTLS(*certFile, *keyFile))
}
}
func homeHandler(w http.ResponseWriter, r *http.Request) {
w.Header().Set("Content-Type", "text/html")
if r.URL.Path != "/" {
w.WriteHeader(http.StatusNotFound)
fmt.Fprint(w, "<html><head></head><body><pre>404 - Not Found</pre></body></html>")
l.Log("404 Handler visited.", l.TraceMessage)
return
}
l.Log("Home Handler visited.", l.TraceMessage)
fmt.Fprint(w, "<html><head></head><body><h1>Welcome to Tyro! The Sierra API helper.</h1></body></html>")
}
func statusHandler(w http.ResponseWriter, r *http.Request) {
w.Header().Set("Content-Type", "text/html")
w.WriteHeader(http.StatusBadRequest)
l.Log("Bare Status Handler visited.", l.TraceMessage)
fmt.Fprint(w, "<html><head></head><body><pre>Available endpoints: /status/bib/[bibID] and /status/item/[itemID]</pre></body></html>")
}
func statusItemHandler(w http.ResponseWriter, r *http.Request) {
setACAOHeader(w, r, *headerACAO)
token, err := getTokenOrError(w, r)
if err != nil {
l.Log(err, l.ErrorMessage)
return
}
itemID := strings.Split(r.URL.Path[len("/status/item/"):], "/")[0]
if itemID == "" {
http.Error(w, "Error, you need to provide an ItemID. /status/item/[ItemID]", http.StatusBadRequest)
l.Log("Bad Request at /status/item/ handler, no ItemID provided.", l.TraceMessage)
return
}
parsedAPIURL, err := parseURLandJoinToPath(*apiURL, sierraapi.ItemRequestEndpoint, itemID)
if err != nil {
http.Error(w, "Server Error.", http.StatusInternalServerError)
l.Log("Internal Server Error at /status/item/ handler, unable to parse url.", l.DebugMessage)
return
}
q := parsedAPIURL.Query()
q.Set("suppressed", "false")
q.Set("deleted", "false")
parsedAPIURL.RawQuery = q.Encode()
resp, err := sierraapi.SendRequestToAPI(parsedAPIURL.String(), token, w, r)
if err != nil {
l.Log(fmt.Sprintf("Internal Server Error at /status/item/, %v", err), l.ErrorMessage)
return
}
if resp.StatusCode == http.StatusUnauthorized {
http.Error(w, "Token is out of date, or is refreshing. Try request again.", http.StatusInternalServerError)
tokenStore.Refresh <- struct{}{}
l.Log("Token is out of date.", l.ErrorMessage)
return
}
if resp.StatusCode == http.StatusNotFound {
http.Error(w, "No item records for that ItemID.", http.StatusNotFound)
l.Log(fmt.Sprintf("No items records match ItemID %v", itemID), l.TraceMessage)
return
}
var responseJSON sierraapi.ItemRecordIn
err = json.NewDecoder(resp.Body).Decode(&responseJSON)
defer resp.Body.Close()
if err != nil {
http.Error(w, "JSON Decoding Error", http.StatusInternalServerError)
l.Log(fmt.Sprintf("Internal Server Error at /status/item/ handler, JSON Decoding Error: %v", err), l.WarnMessage)
return
}
finalJSON, err := json.Marshal(responseJSON.Convert())
if err != nil {
http.Error(w, "JSON Encoding Error", http.StatusInternalServerError)
l.Log(fmt.Sprintf("Internal Server Error at /status/item/ handler, JSON Encoding Error: %v", err), l.WarnMessage)
return
}
l.Log(fmt.Sprintf("Sending response at /status/item handler: %v", responseJSON.Convert()), l.TraceMessage)
w.Header().Set("Content-Type", "application/json;charset=UTF-8")
w.Write(finalJSON)
}
func statusBibHandler(w http.ResponseWriter, r *http.Request) {
setACAOHeader(w, r, *headerACAO)
token, err := getTokenOrError(w, r)
if err != nil {
l.Log(err, l.ErrorMessage)
return
}
bibID := strings.Split(r.URL.Path[len("/status/bib/"):], "/")[0]
if bibID == "" {
http.Error(w, "Error, you need to provide a BibID. /status/bib/[BidID]", http.StatusBadRequest)
l.Log("Bad Request at /status/bib/ handler, no BidID provided.", l.TraceMessage)
return
}
parsedAPIURL, err := parseURLandJoinToPath(*apiURL, sierraapi.ItemRequestEndpoint)
if err != nil {
http.Error(w, "Server Error.", http.StatusInternalServerError)
l.Log("Internal Server Error at /status/bib/ handler, unable to parse url.", l.DebugMessage)
return
}
q := parsedAPIURL.Query()
q.Set("bibIds", bibID)
q.Set("deleted", "false")
q.Set("suppressed", "false")
parsedAPIURL.RawQuery = q.Encode()
resp, err := sierraapi.SendRequestToAPI(parsedAPIURL.String(), token, w, r)
if err != nil {
l.Log(fmt.Sprintf("Internal Server Error at /status/bib/, %v", err), l.ErrorMessage)
return
}
if resp.StatusCode == http.StatusUnauthorized {
http.Error(w, "Token is out of date, or is refreshing. Try request again.", http.StatusInternalServerError)
tokenStore.Refresh <- struct{}{}
l.Log("Token is out of date.", l.ErrorMessage)
return
}
if resp.StatusCode == http.StatusNotFound {
http.Error(w, "No item records for that BibID.", http.StatusNotFound)
l.Log(fmt.Sprintf("No items records match BibID %v", bibID), l.TraceMessage)
return
}
var responseJSON sierraapi.ItemRecordsIn
err = json.NewDecoder(resp.Body).Decode(&responseJSON)
defer resp.Body.Close()
if err != nil {
http.Error(w, "JSON Decoding Error", http.StatusInternalServerError)
l.Log(fmt.Sprintf("Internal Server Error at /status/bib/ handler, JSON Decoding Error: %v", err), l.WarnMessage)
return
}
finalJSON, err := json.Marshal(responseJSON.Convert())
if err != nil {
http.Error(w, "JSON Encoding Error", http.StatusInternalServerError)
l.Log(fmt.Sprintf("Internal Server Error at /status/bib/ handler, JSON Encoding Error: %v", err), l.WarnMessage)
return
}
l.Log(fmt.Sprintf("Sending response at /status/bib/ handler: %v", responseJSON.Convert()), l.TraceMessage)
w.Header().Set("Content-Type", "application/json;charset=UTF-8")
w.Write(finalJSON)
}
func newBibsHandler(w http.ResponseWriter, r *http.Request) {
setACAOHeader(w, r, *headerACAO)
entries := make(map[int]sierraapi.BibRecordOut)
entries, err := getNewItems(entries, time.Now(), w, r)
if err != nil {
return
}
var response sierraapi.BibRecordsOut
for _, entry := range entries {
response = append(response, entry)
}
sort.Sort(sort.Reverse(response))
finalJSON, err := json.Marshal(response)
if err != nil {
http.Error(w, "JSON Encoding Error", http.StatusInternalServerError)
l.Log(fmt.Sprintf("Internal Server Error at /new handler, JSON Encoding Error: %v", err), l.WarnMessage)
return
}
l.Log(fmt.Sprintf("Sending response at /new handler: %v", response), l.TraceMessage)
w.Header().Set("Content-Type", "application/json;charset=UTF-8 ")
w.Write(finalJSON)
}
func getNumberOfEntries(date time.Time, w http.ResponseWriter, r *http.Request) (int, error) {
type totalResponse struct {
Total int `json:"total"`
}
token, err := getTokenOrError(w, r)
if err != nil {
l.Log(err, l.ErrorMessage)
return 0, err
}
parsedAPIURL, err := parseURLandJoinToPath(*apiURL, sierraapi.BibRequestEndpoint)
if err != nil {
http.Error(w, "Server Error.", http.StatusInternalServerError)
l.Log("Internal Server Error at /new handler, unable to parse url.", l.DebugMessage)
return 0, err
}
q := parsedAPIURL.Query()
q.Set("limit", "1")
q.Set("offset", "0")
q.Set("deleted", "false")
q.Set("suppressed", "false")
q.Set("createdDate", fmt.Sprintf("[%v,%v]", date.AddDate(0, 0, -1).Format(time.RFC3339), date.Format(time.RFC3339)))
q.Set("fields", "default")
parsedAPIURL.RawQuery = q.Encode()
resp, err := sierraapi.SendRequestToAPI(parsedAPIURL.String(), token, w, r)
if err != nil {
l.Log(fmt.Sprintf("Internal Server Error at /new, %v", err), l.ErrorMessage)
return 0, err
}
if resp.StatusCode == http.StatusUnauthorized {
http.Error(w, "Token is out of date, or is refreshing. Try request again.", http.StatusInternalServerError)
tokenStore.Refresh <- struct{}{}
l.Log("Token is out of date.", l.ErrorMessage)
return 0, errors.New("Unauthorized")
}
var response totalResponse
err = json.NewDecoder(resp.Body).Decode(&response)
return response.Total, nil
}
func getNewItems(alreadyProcessed map[int]sierraapi.BibRecordOut, date time.Time, w http.ResponseWriter, r *http.Request) (map[int]sierraapi.BibRecordOut, error) {
token, err := getTokenOrError(w, r)
if err != nil {
l.Log(err, l.ErrorMessage)
return nil, err
}
parsedAPIURL, err := parseURLandJoinToPath(*apiURL, sierraapi.BibRequestEndpoint)
if err != nil {
http.Error(w, "Server Error.", http.StatusInternalServerError)
l.Log("Internal Server Error at /new handler, unable to parse url.", l.DebugMessage)
return nil, err
}
total, err := getNumberOfEntries(date, w, r)
if err != nil {
return nil, err
}
offset := 0
needOneMoreDay := false
if total >= *newLimit {
offset = total - *newLimit
} else {
needOneMoreDay = true
}
q := parsedAPIURL.Query()
q.Set("offset", strconv.Itoa(offset))
q.Set("deleted", "false")
q.Set("createdDate", fmt.Sprintf("[%v,%v]", date.AddDate(0, 0, -1).Format(time.RFC3339), date.Format(time.RFC3339)))
q.Set("fields", "marc,default")
q.Set("suppressed", "false")
parsedAPIURL.RawQuery = q.Encode()
resp, err := sierraapi.SendRequestToAPI(parsedAPIURL.String(), token, w, r)
if err != nil {
l.Log(fmt.Sprintf("Internal Server Error at /new, %v", err), l.ErrorMessage)
return nil, err
}
if resp.StatusCode == http.StatusUnauthorized {
http.Error(w, "Token is out of date, or is refreshing. Try request again.", http.StatusInternalServerError)
tokenStore.Refresh <- struct{}{}
l.Log("Token is out of date.", l.ErrorMessage)
return nil, err
}
var response sierraapi.BibRecordsIn
err = json.NewDecoder(resp.Body).Decode(&response)
defer resp.Body.Close()
if err != nil {
http.Error(w, "JSON Decoding Error", http.StatusInternalServerError)
l.Log(fmt.Sprintf("Internal Server Error at /new handler, JSON Decoding Error: %v", err), l.WarnMessage)
return nil, err
}
entries := response.Convert()
for _, entry := range *entries {
alreadyProcessed[entry.BibID] = entry
}
if needOneMoreDay {
return getNewItems(alreadyProcessed, date.Add(time.Duration(1435)*time.Minute*-1), w, r)
} else {
return alreadyProcessed, nil
}
}
func rawRewriter(r *http.Request) {
token, err := tokenStore.Get()
if err != nil {
l.Log("Error at /raw/ handler, token not yet generated.", l.DebugMessage)
}
parsedAPIURL, err := parseURLandJoinToPath(*apiURL, r.URL.Path[len("/raw/"):])
if err != nil {
log.Fatalf("FATAL: %v", err)
}
parsedAPIURL.RawQuery = r.URL.RawQuery
r.URL = parsedAPIURL
err = sierraapi.SetAuthorizationHeaders(r, r, token)
if err != nil {
l.Log("The remote address in an incoming request is not set properly", l.DebugMessage)
}
l.Log(fmt.Sprintf("Sending proxied request: %v", r), l.TraceMessage)
}
func overrideUnsetFlagsFromEnvironmentVariables() {
listOfUnsetFlags := make(map[*flag.Flag]bool)
//Ugly, but only way to get list of unset flags.
flag.VisitAll(func(f *flag.Flag) { listOfUnsetFlags[f] = true })
flag.Visit(func(f *flag.Flag) { delete(listOfUnsetFlags, f) })
for k, _ := range listOfUnsetFlags {
uppercaseName := strings.ToUpper(k.Name)
environmentVariableName := fmt.Sprintf("%v%v", EnvPrefix, uppercaseName)
environmentVariableValue := os.Getenv(environmentVariableName)
if environmentVariableValue != "" {
err := k.Value.Set(environmentVariableValue)
if err != nil {
log.Fatalf("FATAL: Unable to set configuration option %v from environment variable %v, which has a value of \"%v\"",
k.Name, environmentVariableName, environmentVariableValue)
}
}
}
}
func parseURLandJoinToPath(URL string, toJoin ...string) (*url.URL, error) {
parsedURL, err := url.Parse(URL)
if err != nil {
return new(url.URL), errors.New("Unable to parse URL.")
}
for _, element := range toJoin {
parsedURL.Path = path.Join(parsedURL.Path, element)
}
return parsedURL, nil
}
func getTokenOrError(w http.ResponseWriter, r *http.Request) (string, error) {
token, err := tokenStore.Get()
if err != nil {
http.Error(w, "Token Error.", http.StatusInternalServerError)
return token, err
}
if token == tokenstore.UninitialedTokenValue {
l.Log("Waiting for token to initialize...", l.TraceMessage)
select {
case <-tokenStore.Initialized:
tokenStore.Initialized <- struct{}{}
token, err = tokenStore.Get()
if err != nil {
http.Error(w, "Token Error.", http.StatusInternalServerError)
return token, err
}
case <-time.After(time.Second * 30):
http.Error(w, "Token Error.", http.StatusInternalServerError)
return token, errors.New("Unable to get token from TokenStore")
}
}
return token, err
}
func setACAOHeader(w http.ResponseWriter, r *http.Request, headerConfig string) {
if headerConfig == "*" {
w.Header().Set("Access-Control-Allow-Origin", "*")
} else if headerConfig != "" {
possibleOrigins := strings.Split(headerConfig, ";")
for _, okOrigin := range possibleOrigins {
okOrigin = strings.TrimSpace(okOrigin)
if (okOrigin != "") && (okOrigin == r.Header.Get("Origin")) {
w.Header().Set("Access-Control-Allow-Origin", okOrigin)
}
}
}
}