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Parsers.cs
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Parsers.cs
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using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using HtmlAgilityPack;
using System.Text.RegularExpressions;
using KitchenPC.Ingredients;
using KitchenPC.Recipes;
namespace KitchenPC.Parser.Parsers
{
class hRecipeParser : IParser
{
public NLP.Parser NlpParser { get; set; }
public static short ParseDuration(string vt)
{
try
{
var timespan = System.Xml.XmlConvert.ToTimeSpan(vt);
return timespan.TotalMinutes > Int16.MaxValue ? Int16.MaxValue : Convert.ToInt16(timespan.TotalMinutes);
}
catch (FormatException)
{
throw new BadFormatException("Invalid duration: " + vt);
}
}
protected HtmlNode RecursiveSearch(HtmlNode start, Func<HtmlNode, bool> expression)
{
var match = expression(start);
if(match) return start;
return start.ChildNodes
.Select(child => RecursiveSearch(child, expression))
.FirstOrDefault(attempt => attempt != null);
}
protected IEnumerable<HtmlNode> RecursiveCollect(HtmlNode start, Func<HtmlNode, bool> expression)
{
var match = expression(start);
if (match)
yield return start;
foreach (var child in start.ChildNodes)
{
var attempt = RecursiveCollect(child, expression);
foreach(var a in attempt)
yield return a;
}
}
protected HtmlNode FindNodeById(HtmlNode start, string id)
{
var node = RecursiveSearch(start, n =>
{
if (!n.Attributes.Contains("id"))
return false;
return String.CompareOrdinal(n.Attributes["id"].Value.Trim(), id) == 0;
});
return node;
}
protected HtmlNode FindNodeByClass(HtmlNode start, string className)
{
var node = RecursiveSearch(start, n =>
{
if (n == null || n.Attributes == null || !n.Attributes.Contains("class"))
return false;
var classes = n.Attributes["class"].Value.Split(new[] { ' ' }, StringSplitOptions.RemoveEmptyEntries);
return classes.Contains(className, StringComparer.InvariantCultureIgnoreCase);
});
return node;
}
protected HtmlNode[] FindNodesByClass(HtmlNode start, string className)
{
var nodes = RecursiveCollect(start, n =>
{
if (!n.Attributes.Contains("class"))
return false;
var classes = n.Attributes["class"].Value.Split(new[] { ' ' }, StringSplitOptions.RemoveEmptyEntries);
return classes.Contains(className, StringComparer.InvariantCultureIgnoreCase);
}).ToArray();
return nodes;
}
protected virtual string ParseTitle(HtmlNode document)
{
//Required field, look for an element with the class name "fn" (might have other classes too) and parse any child text
//Note: AllRecipes puts a span within the fn tag, we need to support this
var fn = FindNodeByClass(document, "fn");
if (fn == null)
{
throw new MissingNodeException("Document does not contain required node with 'fn' class.");
}
return fn.InnerText.Trim();
}
protected static bool ParseRange(string servings, out byte ret)
{
ret = 0;
var match = Regex.Match(servings, @"\s*(?<low>\d+)\s*(-|to)\s*(?<high>\d+)\s*");
if (match.Success)
{
var low = Convert.ToInt32(match.Groups["low"].Value);
var high = Convert.ToInt32(match.Groups["high"].Value);
var avg = (low + high) / 2;
if (avg > Byte.MaxValue)
avg = Byte.MaxValue;
ret = Convert.ToByte(avg); //Return average of low and high
return true;
}
//TODO: Error checking, large values, other unknown formats
match = Regex.Match(servings, @"\d+"); // "Makes about 12 servings"
return match.Success && Byte.TryParse(match.Value, out ret);
}
protected virtual byte ParseServings(HtmlNode document)
{
//Optional field - need to figure out what to do if this is not found (do we even want those recipes?)
//parse "yield" class, which has no standard format. AllRecipes says "6 to 8 servings", need to be able to parse various forms
var yield = FindNodeByClass(document, "yield");
if (yield == null) throw new MissingNodeException("No parsable yield");
Byte ret;
if (ParseRange(yield.InnerText, out ret))
return ret;
throw new MissingNodeException("No parsable yield");
}
protected virtual string ParseSteps(HtmlNode document)
{
var steps = FindNodeByClass(document, "instructions");
if (steps == null)
throw new MissingHRecipeTag();
var html = steps.InnerHtml; //TODO: Clean up HTML?
return html;
}
protected virtual string CleanHtml(string dirty)
{
var ret = Regex.Replace(dirty, @"[ ]?(id|class|href|src)\s*=\s*(""[^""]+""|'[^']+')", "");
return ret;
}
protected virtual short? ParsePrepTime(HtmlNode document)
{
//TODO: Support non-valuetitle formats
//TODO: Error checking
var yield = FindNodeByClass(document, "preptime");
if (yield == null)
return null;
var span = FindNodeByClass(yield, "value-title");
var ret = ParseDuration(span.Attributes["title"].Value);
return ret;
}
protected virtual short? ParseCookTime(HtmlNode document)
{
var yield = FindNodeByClass(document, "cooktime");
if (yield == null)
return null;
var span = FindNodeByClass(yield, "value-title");
var ret = ParseDuration(span.Attributes["title"].Value);
return ret;
}
protected virtual string ParseDescription(HtmlNode document)
{
//Spec calls this "summary", as does Google and ZipList
//AllRecipes has a summary div which plain text
var yield = FindNodeByClass(document, "summary");
return yield != null ? yield.InnerText.Trim() : null;
}
protected virtual byte ParseRating(HtmlNode document)
{
//No hRecipe spec for rating. Google uses the hReview format, which has a "rating" tag - ZipList also uses "rating" (tricky to parse this)
//AllRecipes puts the rating in an img title, such as "This recipe has an average star rating of 4.4" (Google seems to parse the numeric part)
//Google can also parse "x/y" format such as "4/5" and normalize or "4.5" format, which is assumed to be out of 5
var rating = FindNodeByClass(document, "rating");
if (rating == null) return 0;
var span = FindNodeByClass(rating, "value-title");
if (span != null && span.Attributes.Contains("title"))
{
return ParseRating(span.Attributes["title"].Value);
}
return 0;
}
private byte ParseRating(string p)
{
Single ret;
if (Single.TryParse(p, out ret)) //If it's just a number, parse that
{
return Convert.ToByte(ret);
}
var m = Regex.Match(p, @"^(?<num>\d+)/(?<denom>\d+)$");
if (!m.Success) return 0;
var num = Single.Parse(m.Groups["num"].Value);
var denom = Single.Parse(m.Groups["denom"].Value);
var rounded = Math.Round((num / denom) * 5);
return Convert.ToByte(rounded);
}
protected virtual string ParsePhoto(HtmlNode document)
{
//hRecipe has no spec for photo. ZipList and Google both use a "photo" class, which AllRecipes uses as well as an OpenGraph tag
//AllRecipes has <img> with class="rec-image photo"
var photo = FindNodeByClass(document, "photo");
if (photo != null && photo.Name.Equals("img", StringComparison.InvariantCultureIgnoreCase))
{
return photo.Attributes["src"].Value;
}
return null;
}
public virtual String[] ParseIngredients(HtmlNode document)
{
//Spec says each ingredient has an "ingredient" class, and must include at least one
//Most things will just use plain text, but spec also allows for value/type markup (we might not really care since we use NLP)
var ret = FindNodesByClass(document, "ingredient");
if (ret.Length <= 0) throw new MissingHRecipeTag();
var list = ret.SelectMany(ing => ProcessIngredient(ing.InnerText)).ToArray();
return list;
}
//Pre-process rogue ingredients, such as "salt and pepper"
public static string[] ProcessIngredient(string ing)
{
var i = ing.ToLower().Trim();
//TODO: We need a better system for these ingredients, preferably something that can be stored in the NLP database
if (i.Equals("salt and pepper")) return new[] { "salt", "pepper" };
if (i.Equals("salt & pepper")) return new[] { "salt", "pepper" };
if (i.Equals("salt and black pepper")) return new[] { "salt", "black pepper" };
if (i.Equals("salt & freshly ground black pepper")) return new[] { "salt", "freshly ground black pepper" };
if (i.Equals("salt & freshly ground black pepper, to taste")) return new[] { "salt (to taste)", "freshly ground black pepper (to taste)" };
if (i.Equals("salt and pepper to taste")) return new[] { "salt (to taste)", "pepper (to taste)" };
if (i.Equals("salt and pepper, to taste")) return new[] { "salt (to taste)", "pepper (to taste)" };
if (i.Equals("salt and pepper (to taste)")) return new[] { "salt (to taste)", "pepper (to taste)" };
if (i.Equals("salt & pepper to taste")) return new[] { "salt (to taste)", "pepper (to taste)" };
if (i.Equals("salt & pepper, to taste")) return new[] { "salt (to taste)", "pepper (to taste)" };
if (i.Equals("salt & pepper (to taste)")) return new[] { "salt (to taste)", "pepper (to taste)" };
if (i.Equals("kosher salt & freshly ground black pepper")) return new[] { "kosher salt", "freshly ground black pepper" };
if (i.Equals("salt & fresh ground pepper")) return new[] { "salt", "fresh ground pepper" };
return new[]
{
ing.Trim()
};
}
public virtual string GetCredit(Uri page)
{
return page.Host;
}
protected virtual string PurifyIngredient(string ing)
{
var ret = Regex.Replace(ing, @"\s{2,}|\n", " ").Trim();
ret = ret.Replace(" ", ""); //For some reason, AllRecipes has a lot of "empty" ingredients
return ret;
}
protected virtual void BuildIngredients(Recipe recipe, IEnumerable<String> ingredients, out List<IngredientUsage> valid, out List<string> invalid)
{
valid = new List<IngredientUsage>();
invalid = new List<string>();
foreach (var ing in ingredients)
{
var safeIng = PurifyIngredient(ing);
if (String.IsNullOrEmpty(safeIng))
continue;
var i = NlpParser.Parse(safeIng);
if (i is NLP.Match)
{
valid.Add(i.Usage);
}
else
{
invalid.Add(safeIng);
}
}
}
public virtual ParserResult Parse(Uri page)
{
string[] ings;
List<IngredientUsage> valid;
List<String> missing;
var result = new Recipe();
var doc = new HtmlDocument();
var client = new WebClient();
var html = client.DownloadString(page);
doc.LoadHtml(html);
var root = doc.DocumentNode;
try
{
result.Title = ParseTitle(root);
result.Description = ParseDescription(root);
result.ServingSize = ParseServings(root);
result.PrepTime = ParsePrepTime(root);
result.CookTime = ParseCookTime(root);
result.Method = CleanHtml(ParseSteps(root));
result.AvgRating = ParseRating(root);
result.ImageUrl = ParsePhoto(root); //Parse fully qualified URL, we'll download a local copy just before DB save
ings = ParseIngredients(root);
}
catch (MissingNodeException)
{
return new ParserResult(ParserResult.Status.MissingData);
}
catch (IndexingException)
{
return new ParserResult(ParserResult.Status.BadData);
}
BuildIngredients(result, ings, out valid, out missing);
result.Ingredients = valid.ToArray();
if (missing.Count > 0)
{
return new ParserResult(ParserResult.Status.UnknownIngredient)
{
UnknownIngredients = missing
};
}
result.DateEntered = DateTime.Today;
result.CreditUrl = page.ToString();
result.Credit = GetCredit(page);
return new ParserResult(result);
}
}
[Parser("allrecipes.com")]
class AllRecipesParser : hRecipeParser
{
protected override byte ParseServings(HtmlNode document)
{
//AllRecipes stores servings size in hidden input with the "servings-hdnservings" class
var yield = FindNodeByClass(document, "servings-hdnservings");
if (yield != null && yield.Attributes.Contains("value"))
{
byte ret;
if (Byte.TryParse(yield.Attributes["value"].Value, out ret))
return ret;
}
return base.ParseServings(document);
}
//AllRecipes uses "directions" instead of the standard "instructions"
protected override string ParseSteps(HtmlNode document)
{
var steps = FindNodeByClass(document, "directions");
if(steps == null)
throw new MissingHRecipeTag();
var html = steps.InnerHtml; //TODO: Clean up HTML?
return html;
}
//AllRecipes puts the rating in a non-standard format on the title of an image
protected override byte ParseRating(HtmlNode document)
{
var rating = FindNodeByClass(document, "rating");
if (rating != null)
{
var title = rating.Attributes["title"].Value;
var match = Regex.Match(title, @"\d.\d$"); //Match rating string (rating will appear at the end)
if (match.Success)
{
float r;
if (Single.TryParse(match.Value, out r))
{
return Convert.ToByte(r); //Round to nearest byte
}
}
}
return 0;
}
public override string GetCredit(Uri page)
{
return "AllRecipes";
}
}
[Parser("www.food.com")]
class FoodDotComParser : hRecipeParser
{
//Food.com doesn't use hRecipe "servings" class anywhere
protected override byte ParseServings(HtmlNode document)
{
//AllRecipes stores servings size in hidden input with the "servings-hdnservings" class
var yield = FindNodeById(document, "original_value");
if (yield != null && yield.Attributes.Contains("value"))
{
byte ret;
if(ParseRange(yield.Attributes["value"].Value, out ret))
return ret;
}
return base.ParseServings(document);
}
//Food.com uses the "ingredient" class twice, which results in duplicated ingredients
public override string[] ParseIngredients(HtmlNode document)
{
var nodes = RecursiveCollect(document, n =>
{
return (n.Name == "li" && n.Attributes.Contains("class") && n.Attributes.Contains("itemprop") &&
n.Attributes["class"].Value == "ingredient" && n.Attributes["itemprop"].Value == "ingredients");
}).ToArray();
if (nodes.Length > 0)
{
var list = nodes.SelectMany(ing => ProcessIngredient(ing.InnerText)).ToArray();
return list;
}
throw new MissingHRecipeTag();
}
public override string GetCredit(Uri page)
{
return "Food.com";
}
protected override string ParseSteps(HtmlNode document)
{
var html = base.ParseSteps(document); //We need to parse out some markup
html = Regex.Replace(html, @"\<div\s*class\=\""num\"">\s*\d+\s*\<\/div\>", "");
return html;
}
}
[Parser("www.epicurious.com")]
class EpicuriousParser : hRecipeParser
{
public override string GetCredit(Uri page)
{
return "Epicurious";
}
protected override string ParseSteps(HtmlNode document)
{
var html = base.ParseSteps(document); //We need to parse out some markup
html = Regex.Replace(html, @"\<a\s*href\=\"".+\""\>add your own note\<\/a>", "");
return html;
}
}
}