Add Serializable APIs for DataFrames (#389)

- Add keepValidPagesDF
- Add HTTP status code column to all()
- Add test for keepValidPagesDF
- Addresses #223

src/main/scala/io/archivesunleashed/package.scala

@@ -31,10 +31,10 @@ import org.apache.hadoop.fs.{FileSystem, Path}
 import io.archivesunleashed.matchbox.ExtractDateRDD.DateComponent.DateComponent
 import java.net.URI
 import java.net.URL
-import org.apache.spark.sql.{DataFrame, Row, SparkSession}
+import org.apache.spark.sql.{DataFrame, Dataset, Row, SparkSession}
 import org.apache.spark.sql.types.{BinaryType, IntegerType, StringType, StructField, StructType}
 import org.apache.hadoop.io.LongWritable
-import org.apache.spark.{SerializableWritable, SparkContext}
+import org.apache.spark.{RangePartitioner, SerializableWritable, SparkContext}
 import org.apache.spark.rdd.RDD
 import scala.reflect.ClassTag
 import scala.util.matching.Regex
@@ -83,6 +83,32 @@ package object archivesunleashed {
     }
   }
 
+  /**
+    * A Wrapper class around DF to allow Dfs of type ARCRecord and WARCRecord to be queried via a fluent API.
+    *
+    * To load such an DF, please use [[RecordLoader]] and apply .all() on it.
+    */
+  implicit class WARecordDF(df: DataFrame) extends java.io.Serializable {
+
+    def keepValidPagesDF(): DataFrame = {
+
+      val spark = SparkSession.builder().master("local").getOrCreate()
+      // scalastyle:off
+      import spark.implicits._
+      // scalastyle:on
+
+      df.filter($"crawl_date" isNotNull)
+        .filter(!($"url".rlike(".*robots\\.txt$")) &&
+                  ( $"mime_type_web_server".rlike("text/html") || 
+                    $"mime_type_web_server".rlike("application/xhtml+xml") ||
+                    $"url".rlike("(?i).*htm$") ||
+                    $"url".rlike("(?i).*html$")
+                  )
+               )
+        .filter($"HttpStatus" === 200)
+    }
+  }
+
   /**
     * A Wrapper class around RDD to allow RDDs of type ARCRecord and WARCRecord to be queried via a fluent API.
     *
@@ -94,7 +120,7 @@ package object archivesunleashed {
        Call KeepImages OR KeepValidPages on RDD depending upon the requirement before calling this method */
     def all(): DataFrame = {
       val records = rdd.map(r => Row(r.getCrawlDate, r.getUrl, r.getMimeType,
-          DetectMimeTypeTika(r.getBinaryBytes), r.getContentString, r.getBinaryBytes))
+          DetectMimeTypeTika(r.getBinaryBytes), r.getContentString, r.getBinaryBytes, r.getHttpStatus))
 
       val schema = new StructType()
         .add(StructField("crawl_date", StringType, true))
@@ -103,6 +129,7 @@ package object archivesunleashed {
         .add(StructField("mime_type_tika", StringType, true))
         .add(StructField("content", StringType, true))
         .add(StructField("bytes", BinaryType, true))
+        .add(StructField("HttpStatus", StringType, true))
 
       val sqlContext = SparkSession.builder()
       sqlContext.getOrCreate().createDataFrame(records, schema)

src/test/scala/io/archivesunleashed/RecordDFTest.scala

@@ -0,0 +1,56 @@
+/*
+ * Copyright © 2017 The Archives Unleashed Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package io.archivesunleashed
+
+import com.google.common.io.Resources
+import org.apache.spark.{SparkConf, SparkContext}
+import org.junit.runner.RunWith
+import org.scalatest.junit.JUnitRunner
+import org.scalatest.{BeforeAndAfter, FunSuite}
+
+@RunWith(classOf[JUnitRunner])
+class RecordDFTest extends FunSuite with BeforeAndAfter {
+  private val arcPath = Resources.getResource("arc/example.arc.gz").getPath
+  private val badPath = Resources.getResource("arc/badexample.arc.gz").getPath
+  private val master = "local[4]"
+  private val appName = "example-spark"
+  private var sc: SparkContext = _
+  private val archive = "http://www.archive.org/"
+  private val sloan = "http://www.sloan.org"
+  private val regex = raw"Please visit our website at".r
+
+  before {
+    val conf = new SparkConf()
+      .setMaster(master)
+      .setAppName(appName)
+    conf.set("spark.driver.allowMultipleContexts", "true");
+    sc = new SparkContext(conf)
+  }
+
+  test("keep Valid Pages") {
+    val expected = "http://www.archive.org/"
+    val base = RecordLoader.loadArchives(arcPath, sc).all()
+      .keepValidPagesDF().take(1)(0)(1)
+    assert (base.toString == expected)
+  }
+
+  after {
+    if (sc != null) {
+      sc.stop()
+    }
+  }
+}