public void WriteToOutput(PipeWriter bodyPipe, TagUrlResponse response)
{
var jsonWriter = new Utf8JsonWriter(bodyPipe, state: default);
jsonWriter.WriteStartObject();
jsonWriter.WriteString("url", response.Url);
jsonWriter.WriteString("title", response.Title);
jsonWriter.WriteString("body", response.Body);
jsonWriter.WriteStartArray("existingTags");
foreach (var tag in response.ExistingTags)
{
jsonWriter.WriteStringValue(tag);
}
jsonWriter.WriteEndArray();
jsonWriter.WriteStartArray("suggestions");
foreach (var suggestion in response.Suggestions)
{
jsonWriter.WriteStartObject();
jsonWriter.WriteString("tag", suggestion.Tag);
jsonWriter.WriteStartArray("sources");
foreach (var source in suggestion.Sources)
{
jsonWriter.WriteStringValue(source);
}
jsonWriter.WriteEndArray();
jsonWriter.WriteEndObject();
}
jsonWriter.WriteEndArray();
jsonWriter.WriteEndObject();
jsonWriter.Flush(true);
}
public async Task SuggestTags(HttpContext context)
{
string url = "";
string title = "";
string body = "";
string[] existingTags = { };
if (HttpMethods.IsPost(context.Request.Method))
{
if (context.Request.ContentType != MediaTypeNames.Application.Json &&
context.Request.ContentType != MediaTypeNames.Application.Json + ";charset=utf-8")
{
context.Response.StatusCode = (int)HttpStatusCode.BadRequest;
await context.Response.WriteAsync($"Content type {context.Request.ContentType} not acceptable. Use {MediaTypeNames.Application.Json}");
return;
}
var requestBody = await JsonDocument.ParseAsync(context.Request.Body);
if (!requestBody.RootElement.TryGetProperty("url", out var urlProp))
{
context.Response.StatusCode = (int)HttpStatusCode.BadRequest;
await context.Response.WriteAsync("Missing property 'url'");
return;
}
if (requestBody.RootElement.TryGetProperty("body", out var bodyProp))
{
body = bodyProp.GetString() ?? "";
}
if (requestBody.RootElement.TryGetProperty("title", out var titleProp))
{
title = titleProp.GetString() ?? "";
}
if (requestBody.RootElement.TryGetProperty("existingTags", out var existingTagsProp))
{
existingTags = existingTagsProp.EnumerateArray().Select(e => e.GetString()).ToArray();
}
url = urlProp.GetString();
}
else
{
if (!context.Request.Query.ContainsKey("url"))
{
context.Response.StatusCode = (int)HttpStatusCode.BadRequest;
await context.Response.WriteAsync("Missing query string parameter 'url'");
return;
}
url = context.Request.Query["url"].First();
}
var key = ("tagSuggestions", url, title, body);
var suggestions =
await _suggestionsCache.GetOrCreateAsync(key,
async cacheEntry => await _tagUrlService
.SuggestionsForAsync(url, title, body, existingTags));
var response = new TagUrlResponse
{
Url = url,
Title = title,
Body = body,
ExistingTags = existingTags,
Suggestions = suggestions
};
context.Response.ContentType = MediaTypeNames.Application.Json;
WriteToOutput(context.Response.BodyPipe, response);
// Question: Do I really need this flushasync here? or should that happen somewhere else?
await context.Response.BodyPipe.FlushAsync();
}