add first parsing utilities

scraping/parse.R

@@ -0,0 +1,120 @@
+source("config.R")
+source("../utils/helpers.R")
+library("xml2")
+library(tibble)
+library(magrittr)
+
+# for usage see the example at the end
+
+# this reads all currently parseable data from one xml
+read_one <- function(name) {
+    x <- read_xml(paste0(DOWNLOAD_DIR, name))
+    cs <- xml_children(x)
+
+    verlauf <- xml_find_first(x, "sitzungsverlauf")
+    rednerl <- xml_find_first(x, "rednerliste")
+
+    xml_children(rednerl) %>%
+        parse_rednerliste() ->
+        redner
+
+    xml_children(verlauf) %>%
+        xml_find_all("rede") %>%
+        parse_redenliste() ->
+        res
+    list(redner = redner, reden = res$reden, talks = res$talks)
+}
+
+xml_get <- function(node, name) {
+    res <- xml_text %$% xml_find_all(node, name)
+    if (length(res) == 0) NA_character_
+    else res
+}
+
+# parse one redner
+parse_redner <- function(redner_xml) {
+    redner_id <- xml_attr(redner_xml, "id")
+    nm <- xml_child(redner_xml)
+    vorname <- xml_get(nm, "vorname")
+    nachname <- xml_get(nm, "nachname")
+    fraktion <- xml_get(nm, "fraktion")
+    titel <- xml_get(nm, "titel")
+    rolle <- xml_find_all(nm, "rolle")
+    if (length(rolle) > 0) {
+        rolle_lang <- xml_get(rolle, "rolle_lang")
+        rolle_kurz <- xml_get(rolle, "rolle_kurz")
+    } else rolle_kurz <- rolle_lang <- NA_character_
+    c(id = redner_id, vorname = vorname, nachname = nachname, fraktion = fraktion, titel = titel,
+      rolle_kurz = rolle_kurz, rolle_lang = rolle_lang)
+}
+
+# parse one rede
+# returns: - a rede (with rede id and redner id)
+#          - all talks appearing in the rede (with corresponding content)
+parse_rede <- function(rede_xml) {
+    rede_id <- xml_attr(rede_xml, "id")
+    cs <- xml_children(rede_xml)
+    cur_redner <- NA_character_
+    principal_redner <- NA_character_
+    cur_content <- ""
+    reden <- list()
+    for (node in cs) {
+        if (xml_name(node) == "p") {
+            if (xml_attr(node, "klasse") == "redner") {
+                if (!is.na(cur_redner)) {
+                    rede <- c(rede_id = rede_id,
+                              redner = cur_redner,
+                              content = cur_content)
+                    reden <- c(reden, list(rede))
+                    cur_content <- ""
+                } else {
+                    principal_redner <- xml_child(node) %>% xml_attr("id")
+                }
+                cur_redner <- xml_child(node) %>% xml_attr("id")
+            } else {
+                cur_content <- paste0(cur_content, xml_text(node), sep="\n")
+            }
+        }
+    }
+    rede <- c(rede_id = rede_id,
+              redner = cur_redner,
+              content = cur_content)
+    reden <- c(reden, list(rede))
+    list(rede = c(id = rede_id, redner = principal_redner),
+         parts = reden)
+}
+
+# creates a tibble of reden and a tibble of talks from a list of xml nodes representing reden
+parse_redenliste <- function(redenliste_xml) {
+    d <- sapply(redenliste_xml, parse_rede)
+    reden <- simplify2array(d["rede", ])
+    parts <- simplify2array %$% unlist(d["parts", ], recursive=FALSE)
+    list(reden = tibble(id = reden["id",], redner = reden["redner",]),
+         talks = tibble(rede_id = parts["rede_id", ],
+                        redner = parts["redner", ],
+                        content = parts["content", ]))
+}
+
+# create a tibble of redner from a list of xml nodes representing redner
+parse_rednerliste <- function(rednerliste_xml) {
+    d <- sapply(rednerliste_xml, parse_redner)
+    tibble(id = d["id",],
+           vorname = d["vorname",],
+           nachname = d["nachname",],
+           fraktion = d["fraktion",],
+           titel = d["titel",],
+           rolle_kurz = d["rolle_kurz",],
+           rolle_lang = d["rolle_lang",])
+}
+
+# -------------------------------
+# EXAMPLE USE
+
+# make sure data ist downloaded via fetch.R
+res <- read_one("19038-data.xml")
+
+res$redner
+res$reden
+res$talks
+
+# -------------------------------