/// <summary>
/// 更新今日图片。
/// </summary>
/// <param name="todayImage">待更新的今日图片。</param>
public async Task UpdateTodayImageAsync(TodayImage todayImage)
{
Preferences.Set(ExpiresAtKey, todayImage.ExpiresAt);
if (todayImage.Scope == TodayImage.ModificationScope.ExpiresAt)
{
return;
}
Preferences.Set(FullStartDateKey, todayImage.FullStartDate);
Preferences.Set(CopyrightKey, todayImage.Copyright);
Preferences.Set(CopyrightLinkKey, todayImage.CopyrightLink);
using (var imageFileStream =
new FileStream(TodayImagePath, FileMode.Create))
{
await imageFileStream.WriteAsync(todayImage.ImageBytes, 0,
todayImage.ImageBytes.Length);
}
}
/// <summary>
/// 获得今日图片。
/// </summary>
/// <param name="includingImageStream">包含图片流。</param>
public async Task <TodayImage> GetTodayImageAsync(
bool includingImageStream)
{
var todayImage = new TodayImage
{
FullStartDate =
Preferences.Get(FullStartDateKey, FullStartDateDefault),
ExpiresAt = Preferences.Get(ExpiresAtKey, ExpiresAtDefault),
Copyright = Preferences.Get(CopyrightKey, CopyrightDefault),
CopyrightLink =
Preferences.Get(CopyrightLinkKey, CopyrightLinkDefault)
};
if (!File.Exists(TodayImagePath))
{
using (var imageFileStream =
new FileStream(TodayImagePath, FileMode.OpenOrCreate))
using (var imageAssetStream = Assembly.GetExecutingAssembly()
.GetManifestResourceStream("NEUVolunteer." + FileName))
{
await imageAssetStream.CopyToAsync(imageFileStream);
}
}
if (!includingImageStream)
{
return(todayImage);
}
var imageMemoryStream = new MemoryStream();
using (var imageFileStream =
new FileStream(TodayImagePath, FileMode.Open))
{
await imageFileStream.CopyToAsync(imageMemoryStream);
}
todayImage.ImageBytes = imageMemoryStream.GetBuffer();
return(todayImage);
}
CheckUpdateAsync()
{
var todayImage = await todayImageStorage.GetTodayImageAsync(false);
if (todayImage.ExpiresAt > DateTime.Now)
{
return(new TodayImageServiceCheckUpdateResult
{
HasUpdate = false
});
}
BingImageOfTheDayImage bingImage;
using (var httpClient = new HttpClient())
{
HttpResponseMessage response;
try
{
response = await httpClient.GetAsync(
"https://www.bing.com/HPImageArchive.aspx?format=js&idx=0&n=1&mkt=zh-CN");
response.EnsureSuccessStatusCode();
}
catch (Exception e)
{
await alertService.ShowAlertAsync(
ErrorMessages.HTTP_CLIENT_ERROR_TITLE,
ErrorMessages.HttpClientErrorMessage(Server, e.Message),
ErrorMessages.HTTP_CLIENT_ERROR_BUTTON);
return(new TodayImageServiceCheckUpdateResult
{
HasUpdate = false
});
}
var json = await response.Content.ReadAsStringAsync();
bingImage = JsonConvert
.DeserializeObject <BingImageOfTheDay>(json).Images[0];
}
var bingImageFullStartDate = DateTime.ParseExact(
bingImage.Fullstartdate, "yyyyMMddHHmm",
CultureInfo.InvariantCulture);
var todayImageFullStartDate = DateTime.ParseExact(
todayImage.FullStartDate, "yyyyMMddHHmm",
CultureInfo.InvariantCulture);
if (bingImageFullStartDate <= todayImageFullStartDate)
{
todayImage.ExpiresAt = DateTime.Now.AddHours(2);
todayImage.Scope = TodayImage.ModificationScope.ExpiresAt;
await todayImageStorage.UpdateTodayImageAsync(todayImage);
return(new TodayImageServiceCheckUpdateResult
{
HasUpdate = false
});
}
todayImage = new TodayImage
{
FullStartDate = bingImage.Fullstartdate,
ExpiresAt = bingImageFullStartDate.AddDays(1),
Copyright = bingImage.Copyright,
CopyrightLink = bingImage.Copyrightlink,
Scope = TodayImage.ModificationScope.All
};
using (var httpClient = new HttpClient())
{
HttpResponseMessage response;
try
{
response =
await httpClient.GetAsync("https://www.bing.com" +
bingImage.Url);
response.EnsureSuccessStatusCode();
}
catch (Exception e)
{
await alertService.ShowAlertAsync(
ErrorMessages.HTTP_CLIENT_ERROR_TITLE,
ErrorMessages.HttpClientErrorMessage(Server, e.Message),
ErrorMessages.HTTP_CLIENT_ERROR_BUTTON);
return(new TodayImageServiceCheckUpdateResult
{
HasUpdate = false
});
}
todayImage.ImageBytes =
await response.Content.ReadAsByteArrayAsync();
}
await todayImageStorage.UpdateTodayImageAsync(todayImage);
return(new TodayImageServiceCheckUpdateResult
{
HasUpdate = true, TodayImage = todayImage
});
}
