Exemplo n.º 1
0
		/// <summary>
		/// Retrieves GTFS data for a specified agency.
		/// Data will be retrieved from an in-memory list if available and up-to-date.
		/// Otherwise the GTFS data will be requested from the GTFS Data Exchange website
		/// and stored for future use.
		/// </summary>
		/// <param name="agencyId">The GTFS-Data-Exchange agency identifier.</param>
		/// <param name="lastModified">If an "If-Modified-Since" header is present, that value can be used here. Otherwise omit.</param>
		/// <param name="etags">If the HTTP request contains "If-None-Match", it can be passed in here. Otherwise it can be omitted.</param>
		/// <returns>Returns a <see cref="FeedRequestResponse"/>.</returns>
		/// <exception cref="ArgumentException">Thrown if <paramref name="agencyId"/> is <see langword="null"/> or consists only of whitespace.</exception>
		/// <exception cref="AgencyQueryException">Thrown if the query to gtfs-data-exchange for information fails.</exception>
		public FeedRequestResponse GetGtfs(string agencyId,
DateTimeOffset? lastModified = default(DateTimeOffset?),
			IEnumerable<EntityTagHeaderValue> etags = null)
		{
			if (string.IsNullOrWhiteSpace(agencyId))
			{
				throw new ArgumentException("The agencyId was not provided.");
			}

			// Get the record with the matching agency ID.
			var feedRecord = _feedList.FirstOrDefault(r => string.Compare(r.AgencyId, agencyId, true) == 0);

			// Check to see if there are matching Etags...
			if (feedRecord != null && feedRecord.Etag != null && etags != null)
			{
				var match = etags.FirstOrDefault(et => et == feedRecord.Etag);
				if (match != null)
				{
					return new FeedRequestResponse { NotModified = true };
				}
			}

			HttpClient client = null;
			GtfsFeed gtfs = feedRecord != null ? feedRecord.GtfsData : null;
			EntityTagHeaderValue outEtag = null;

			AgencyResponse agencyResponse = null;
			FeedRequestResponse output = null;

			try
			{
				// Check for an existing record...

				// Check online to see if there is a newer feed available. 
				// This will be skipped if there is no matching GTFS feed stored for the specified agency.
				const string urlFmt = "http://www.gtfs-data-exchange.com/api/agency?agency={0}";
				Uri uri = new Uri(string.Format(urlFmt, agencyId));

				client = new HttpClient();
				client.DefaultRequestHeaders.IfModifiedSince = lastModified;
				if (etags != null)
				{
					foreach (var etag in etags)
					{
						client.DefaultRequestHeaders.IfNoneMatch.Add(etag);
					}
				}

				client.GetAsync(uri).ContinueWith((t) =>
				{
					outEtag = t.Result.Headers.ETag;
					if (t.Result.StatusCode == HttpStatusCode.NotModified)
					{
						output = new FeedRequestResponse
						{
							NotModified = true
						};
					}
					else if (t.Result.StatusCode == HttpStatusCode.OK)
					{
						t.Result.Content.ReadAsStreamAsync().ContinueWith(streamTask => {
							using (var streamReader = new StreamReader(streamTask.Result))
							using (var jsonReader = new JsonTextReader(streamReader))
							{
								var serializer = JsonSerializer.Create();
								agencyResponse = serializer.Deserialize<AgencyResponse>(jsonReader);
							}
						}).Wait();
					}
				}).Wait();

				// If the request for GTFS info returned a "Not Modified" response, return now.
				if (output == null)
				{
					if (agencyResponse.status_code != 200)
					{
						throw new AgencyQueryException(agencyResponse);
					}

					if (lastModified.HasValue && lastModified.Value >= agencyResponse.data.agency.date_last_updated.FromJSDateToDateTimeOffset())
					{
						if (feedRecord == null)
						{
							feedRecord = new FeedRecord
							{
								DateLastUpdated = lastModified.Value,
								Etag = outEtag
							};
						}
					}
					else
					{

						if (feedRecord == null || (agencyResponse.data.agency.date_last_updated.FromJSDateToDateTimeOffset() > feedRecord.DateLastUpdated))
						{
							// Get the GTFS file...
							Uri zipUri = new Uri(String.Join("/", agencyResponse.data.agency.dataexchange_url.TrimEnd('/'), "latest.zip"));

							// TODO: make the request and parse the GTFS...
							if (client == null)
							{
								client = new HttpClient();
							}
							else
							{
								client.DefaultRequestHeaders.Clear();
							}

							client.GetStreamAsync(zipUri).ContinueWith(t =>
							{
								t.Result.ReadGtfsAsync().ContinueWith(gtfsTask => {
									gtfs = gtfsTask.Result;
									// Delete the existing feedRecord.
									if (feedRecord != null)
									{
										_feedList.Remove(feedRecord);
									}
									feedRecord = new FeedRecord
									{
										GtfsData = gtfs,
										AgencyId = agencyId,
										DateLastUpdated = agencyResponse.data.agency.date_last_updated.FromJSDateToDateTimeOffset(),
										Etag = outEtag
									};
									// Add the new GTFS feed data to the in-memory collection.
									_feedList.Add(feedRecord);
								}).Wait();
							}).Wait();
						}
					}
				}

			}
			finally
			{
				if (client != null)
				{
					client.Dispose();
				}
			}




			return new FeedRequestResponse
			{
				FeedRecord = feedRecord
			};


		}
Exemplo n.º 2
0
        /// <summary>
        /// Retrieves GTFS data for a specified agency.
        /// Data will be retrieved from an in-memory list if available and up-to-date.
        /// Otherwise the GTFS data will be requested from the GTFS Data Exchange website
        /// and stored for future use.
        /// </summary>
        /// <param name="agencyId">The GTFS-Data-Exchange agency identifier.</param>
        /// <param name="lastModified">If an "If-Modified-Since" header is present, that value can be used here. Otherwise omit.</param>
        /// <param name="etags">If the HTTP request contains "If-None-Match", it can be passed in here. Otherwise it can be omitted.</param>
        /// <returns>Returns a <see cref="FeedRequestResponse"/>.</returns>
        /// <exception cref="ArgumentException">Thrown if <paramref name="agencyId"/> is <see langword="null"/> or consists only of whitespace.</exception>
        /// <exception cref="AgencyQueryException">Thrown if the query to gtfs-data-exchange for information fails.</exception>
        public FeedRequestResponse GetGtfs(string agencyId,
                                           DateTimeOffset?lastModified = default(DateTimeOffset?),
                                           IEnumerable <EntityTagHeaderValue> etags = null)
        {
            if (string.IsNullOrWhiteSpace(agencyId))
            {
                throw new ArgumentException("The agencyId was not provided.");
            }

            // Get the record with the matching agency ID.
            var feedRecord = _feedList.FirstOrDefault(r => string.Compare(r.AgencyId, agencyId, true) == 0);

            // Check to see if there are matching Etags...
            if (feedRecord != null && feedRecord.Etag != null && etags != null)
            {
                var match = etags.FirstOrDefault(et => et == feedRecord.Etag);
                if (match != null)
                {
                    return(new FeedRequestResponse {
                        NotModified = true
                    });
                }
            }

            HttpClient           client  = null;
            GtfsFeed             gtfs    = feedRecord != null ? feedRecord.GtfsData : null;
            EntityTagHeaderValue outEtag = null;

            AgencyResponse      agencyResponse = null;
            FeedRequestResponse output         = null;

            try
            {
                // Check for an existing record...

                // Check online to see if there is a newer feed available.
                // This will be skipped if there is no matching GTFS feed stored for the specified agency.
                const string urlFmt = "http://www.gtfs-data-exchange.com/api/agency?agency={0}";
                Uri          uri    = new Uri(string.Format(urlFmt, agencyId));

                client = new HttpClient();
                client.DefaultRequestHeaders.IfModifiedSince = lastModified;
                if (etags != null)
                {
                    foreach (var etag in etags)
                    {
                        client.DefaultRequestHeaders.IfNoneMatch.Add(etag);
                    }
                }

                client.GetAsync(uri).ContinueWith((t) =>
                {
                    outEtag = t.Result.Headers.ETag;
                    if (t.Result.StatusCode == HttpStatusCode.NotModified)
                    {
                        output = new FeedRequestResponse
                        {
                            NotModified = true
                        };
                    }
                    else if (t.Result.StatusCode == HttpStatusCode.OK)
                    {
                        t.Result.Content.ReadAsStreamAsync().ContinueWith(streamTask => {
                            using (var streamReader = new StreamReader(streamTask.Result))
                                using (var jsonReader = new JsonTextReader(streamReader))
                                {
                                    var serializer = JsonSerializer.Create();
                                    agencyResponse = serializer.Deserialize <AgencyResponse>(jsonReader);
                                }
                        }).Wait();
                    }
                }).Wait();

                // If the request for GTFS info returned a "Not Modified" response, return now.
                if (output == null)
                {
                    if (agencyResponse.status_code != 200)
                    {
                        throw new AgencyQueryException(agencyResponse);
                    }

                    if (lastModified.HasValue && lastModified.Value >= agencyResponse.data.agency.date_last_updated.FromJSDateToDateTimeOffset())
                    {
                        if (feedRecord == null)
                        {
                            feedRecord = new FeedRecord
                            {
                                DateLastUpdated = lastModified.Value,
                                Etag            = outEtag
                            };
                        }
                    }
                    else
                    {
                        if (feedRecord == null || (agencyResponse.data.agency.date_last_updated.FromJSDateToDateTimeOffset() > feedRecord.DateLastUpdated))
                        {
                            // Get the GTFS file...
                            Uri zipUri = new Uri(String.Join("/", agencyResponse.data.agency.dataexchange_url.TrimEnd('/'), "latest.zip"));

                            // TODO: make the request and parse the GTFS...
                            if (client == null)
                            {
                                client = new HttpClient();
                            }
                            else
                            {
                                client.DefaultRequestHeaders.Clear();
                            }

                            client.GetStreamAsync(zipUri).ContinueWith(t =>
                            {
                                t.Result.ReadGtfsAsync().ContinueWith(gtfsTask => {
                                    gtfs = gtfsTask.Result;
                                    // Delete the existing feedRecord.
                                    if (feedRecord != null)
                                    {
                                        _feedList.Remove(feedRecord);
                                    }
                                    feedRecord = new FeedRecord
                                    {
                                        GtfsData        = gtfs,
                                        AgencyId        = agencyId,
                                        DateLastUpdated = agencyResponse.data.agency.date_last_updated.FromJSDateToDateTimeOffset(),
                                        Etag            = outEtag
                                    };
                                    // Add the new GTFS feed data to the in-memory collection.
                                    _feedList.Add(feedRecord);
                                }).Wait();
                            }).Wait();
                        }
                    }
                }
            }
            finally
            {
                if (client != null)
                {
                    client.Dispose();
                }
            }



            return(new FeedRequestResponse
            {
                FeedRecord = feedRecord
            });
        }