public async Task <WikiImage> GetImage()
{
HttpClient client = new HttpClient();
string reqUri = API_BASE +
"?action=query" +
"&prop=imageinfo|categories|globalusage" +
"&iiprop=url|size|extmetadata|mediatype" +
"&iiurlheight=1080" +
"&format=json" +
"&generator=random" +
"&grnnamespace=6";
var productValue = new ProductInfoHeaderValue("ImageDescBot", "1.0");
var commentValue = new ProductInfoHeaderValue("(+https://github.com/smurfpandey/ImageDescribeBot)");
try
{
client.DefaultRequestHeaders.UserAgent.Add(productValue);
client.DefaultRequestHeaders.UserAgent.Add(commentValue);
// make api rquest to wikimedia
string response = await client.GetStringAsync(reqUri);
JObject jObj = JsonConvert.DeserializeObject <JObject>(response);
JToken imageData = jObj["query"]["pages"].First.First;
WikimediaResponse objWImage = imageData.ToObject <WikimediaResponse>();
if (IsValidImage(objWImage))
{
return(objWImage.ImageInfo[0]);
}
}
catch (Exception ex)
{
_logger.Error("error getting image from wikipedia", ex);
}
return(null);
}
private bool IsValidImage(WikimediaResponse objWImage)
{
WikiImage objIInfo = objWImage.ImageInfo[0];
// check that the file is actually a picture
if (objIInfo.MediaType != "BITMAP")
{
return(false);
}
// Make sure the picture is big enough
if (objIInfo.Width <= 50 || objIInfo.Height <= 50)
{
return(false);
}
// Make sure the format is supported
string thisExtn = Path.GetExtension(objIInfo.Url);
if (Array.IndexOf(FORMATS, thisExtn) < 0)
{
return(false);
}
// We got a picture, now let's verify we can use it.
//Check file name for bad words
if (objCensor.IsBlacklisted(objWImage.Title))
{
_logger.InfoFormat("Image discarded, {0}. badword in page title: {1}", objIInfo.DescriptionUrl, objWImage.Title);
return(false);
}
// Check picture title for bad words
if (objCensor.IsBlacklisted(objIInfo.Metadata.ObjectName.value.ToString()))
{
_logger.InfoFormat("Image discarded, {0}. badword in picture title: {1}", objIInfo.DescriptionUrl, objIInfo.Metadata.ObjectName.value.ToString());
return(false);
}
// Check restrictions for more bad words
if (objCensor.IsBlacklisted(objIInfo.Metadata.Restrictions.value.ToString()))
{
_logger.InfoFormat("Image discarded, {0}. badword in restrictions: {1}", objIInfo.DescriptionUrl, objIInfo.Metadata.Restrictions.value.ToString());
return(false);
}
// Check file description for bad words
if (objIInfo.Metadata.ImageDescription != null)
{
string cleanedDescription = Utility.GetTextFromHtml(objIInfo.Metadata.ImageDescription.value.ToString());
if (objCensor.IsBlacklisted(cleanedDescription))
{
_logger.InfoFormat("Image discarded, {0}. badword in image description: {1}", objIInfo.DescriptionUrl, cleanedDescription);
return(false);
}
if (objCensor.ShouldFilterForPhrase(cleanedDescription))
{
_logger.InfoFormat("Image discarded, {0}. blacklisted phrase in image description: {1}", objIInfo.DescriptionUrl, cleanedDescription);
return(false);
}
}
// The mediawiki API is awful, there's another list of categories which
// is not the same as the one requested by asking for "categories".
// Fortunately it's still in the API response, under extmetadata.
List <string> lstCateg = new List <string>();
lstCateg.Add(objIInfo.Metadata.Categories.value.ToString());
foreach (dynamic objCateg in objWImage.Category)
{
lstCateg.Add(objCateg.title.ToString());
}
if (objCensor.ShouldFilterForCategory(lstCateg))
{
_logger.InfoFormat("Image discarded, {0}. blacklisted phrase in categories", objIInfo.DescriptionUrl);
return(false);
}
// #TODO:: check parent categories for each category in metadata,
// and compare them against the blacklist too. This will require
// extra API calls
// if the picture is used in any wikipage with unwanted themes, we probably
// don't want to use it.
foreach (dynamic wikipage in objWImage.GlobalUsage)
{
if (objCensor.IsBlacklisted(wikipage.title.ToString()))
{
_logger.InfoFormat("Image discarded, {0}. page usage {1}", objIInfo.DescriptionUrl, wikipage.title.ToString());
return(false);
}
if (objCensor.ShouldFilterForCategory(wikipage.title.ToString()))
{
_logger.InfoFormat("Image discarded, {0}. page usage {1}", objIInfo.DescriptionUrl, wikipage.title.ToString());
return(false);
}
}
return(true);
}
