Manipulação de XML

Prof. Walmes Marques Zeviani

02 Mar 2017

Definir e mostrar exemplos de Web API de formatos XML e JSON.
Ler e manipular dados XML com o pacote XML.

API WEB

API: Application Program Interface = Interface de Programação de Aplicativos (https://www.tecmundo.com.br/programacao/1807-o-que-e-api-.htm).
Web API: Uma web API server-side é uma interface programática consistente de um ou mais endpoints publicamente expostos para um sistema definido de mensagens pedido-resposta, tipicamente expressado em JSON ou XML, que é exposto via a internet—mais comumente por meio de um servidor web baseado em HTTP (https://pt.wikipedia.org/wiki/Web_API).
É o forma de dar acesso público e seguro para o seu bando de dados.

The Open Movie Database

# Consulta informações sobre o filme Titanic.
url <- "http://www.omdbapi.com/?t=%s&r=xml"
url <- sprintf(url, "titanic")
browseURL(url)

# Faz busca por filmes com o termo batman.
url <- "http://www.omdbapi.com/?s=%s&r=xml"
url <- sprintf(url, "batman")
browseURL(url)

Earthquake Catalog API

Dados sobre terremotos e abalos sísmicos.
Não requer conta, dados públicos em vários formatos.
Documentação da API: https://earthquake.usgs.gov/fdsnws/event/1/.

# Número de ocorrências para no intervalo fornecido.
url <- paste0("https://earthquake.usgs.gov/fdsnws/event/1/",
              "count?",
              "format=xml&",
              "starttime=2017-02-02T12:00:00&",
              "endtime=2017-02-02T13:00:00")
browseURL(url)

# Detalhes das ocorrências no intervalo fornecido.
url <- paste0("https://earthquake.usgs.gov/fdsnws/event/1/",
              "query?",
              "format=xml&",
              "starttime=2017-02-02T12:00:00&",
              "endtime=2017-02-02T13:00:00")
browseURL(url)

Open Weather Map API

Dados climáticos.
Requer criar conta mas possui plano free.
Planos: http://openweathermap.org/price#weather.
ID das cidades: http://bulk.openweathermap.org/sample/city.list.json.gz.

# JSON com informações de Curitiba.
# {"_id": 6322752,
#  "name": "Curitiba",
#  "country": "BR",
#  "coord": {"lon": -49.290821, "lat": -25.50395}}

url <- paste0("http://samples.openweathermap.org/data/2.5/",
              "weather?id=%d&appid=%s")
url <- sprintf(url,
               6322752,
               "6eb4d970f22e507866028152781d8dd5")
url

browseURL(url)

Mais APIs

Atenção

APIs são largamente utilizadas para liberação/consumo de dados entre aplicativos e para usuários.
XML e JSON são os formatos mais utilizados.
Saber colher e manipular informação em XML e JSON é fundamental na Era Data Science & Big Data.
Neste curso usaremos formatos XML-based e JSON amplamente.

Dados colhidos da API

# Faz busca por filmes com o termo batman.
url <- "http://www.omdbapi.com/?s=%s&r=xml"
# url <- sprintf(url, "rocky")
# url <- sprintf(url, "terminator")
# url <- sprintf(url, "rambo")
url <- sprintf(url, "resident evil")
url

## [1] "http://www.omdbapi.com/?s=resident evil&r=xml"

# browseURL(url)

O documento XML

library(XML)
doc <- xmlParse(url)

# Classe do objeto.
class(doc)

## [1] "XMLInternalDocument" "XMLAbstractDocument"

# Métodos disponíveis para a classe.
methods(class = "XMLInternalDocument")

##  [1] addChildren             coerce                 
##  [3] docName<-               docName                
##  [5] free                    getEncoding            
##  [7] initialize              print                  
##  [9] processXInclude         readKeyValueDB         
## [11] readSolrDoc             saveXML                
## [13] show                    slotsFromS3            
## [15] summary                 xmlChildren            
## [17] xmlClone                [                      
## [19] [[                      xmlNamespaceDefinitions
## [21] xmlRoot                 xmlSourceFunctions     
## [23] xmlSourceSection        xmlSource              
## [25] xmlToDataFrame          xpathApply             
## see '?methods' for accessing help and source code

# Nome do arquivo origem.
docName(doc)

## [1] "http://www.omdbapi.com/?s=resident%20evil&r=xml"

# Mostra o conteúdo.
show(doc)

## <?xml version="1.0" encoding="utf-8"?>
## <root totalResults="67" response="True">
##   <result title="Resident Evil" year="2002" imdbID="tt0120804" type="movie" poster="https://images-na.ssl-images-amazon.com/images/M/MV5BN2Y2MTljNjMtMDRlNi00ZWNhLThmMWItYTlmZjYyZDk4NzYxXkEyXkFqcGdeQXVyNjQ2MjQ5NzM@._V1_SX300.jpg"/>
##   <result title="Resident Evil: Apocalypse" year="2004" imdbID="tt0318627" type="movie" poster="https://images-na.ssl-images-amazon.com/images/M/MV5BMTc1NTUxMzk0Nl5BMl5BanBnXkFtZTcwNDQ1MDIzMw@@._V1_SX300.jpg"/>
##   <result title="Resident Evil: Extinction" year="2007" imdbID="tt0432021" type="movie" poster="https://images-na.ssl-images-amazon.com/images/M/MV5BNDQ0MWI3MmEtMzM0OC00Y2ViLWE4MDItMzNhNmY1ZTdjMWE2XkEyXkFqcGdeQXVyMTQxNzMzNDI@._V1_SX300.jpg"/>
##   <result title="Resident Evil: Afterlife" year="2010" imdbID="tt1220634" type="movie" poster="https://images-na.ssl-images-amazon.com/images/M/MV5BMTkxNzM3OTg5OF5BMl5BanBnXkFtZTcwMDA5MDA2Mw@@._V1_SX300.jpg"/>
##   <result title="Resident Evil: Retribution" year="2012" imdbID="tt1855325" type="movie" poster="https://images-na.ssl-images-amazon.com/images/M/MV5BMTA2NTkwNjUxNTZeQTJeQWpwZ15BbWU3MDE2OTMxMTg@._V1_SX300.jpg"/>
##   <result title="Resident Evil: The Final Chapter" year="2016" imdbID="tt2592614" type="movie" poster="https://images-na.ssl-images-amazon.com/images/M/MV5BMTc0Mzc2OTQ0Ml5BMl5BanBnXkFtZTgwOTQ5MjE4MDI@._V1_SX300.jpg"/>
##   <result title="Resident Evil: Degeneration" year="2008" imdbID="tt1174954" type="movie" poster="https://images-na.ssl-images-amazon.com/images/M/MV5BMTgwMDE4NzcxMl5BMl5BanBnXkFtZTcwNjU1NjcwMg@@._V1_SX300.jpg"/>
##   <result title="Resident Evil: Damnation" year="2012" imdbID="tt1753496" type="movie" poster="https://images-na.ssl-images-amazon.com/images/M/MV5BNzg2ODUxOTIzN15BMl5BanBnXkFtZTcwMDM0NzAzOA@@._V1_SX300.jpg"/>
##   <result title="Resident Evil 4" year="2005" imdbID="tt0397042" type="game" poster="http://ia.media-imdb.com/images/M/MV5BMTU1NjY2MDM4Nl5BMl5BanBnXkFtZTgwMzk0MTU3MDE@._V1_SX300.jpg"/>
##   <result title="Resident Evil 5" year="2009" imdbID="tt0473298" type="game" poster="http://ia.media-imdb.com/images/M/MV5BMTk3MDMzNzMxMV5BMl5BanBnXkFtZTcwNDYxNTMxNg@@._V1_SX300.jpg"/>
## </root>
##

Propriedades do elemento root

root <- xmlRoot(doc)

# Classe do objeto.
class(root)

## [1] "XMLInternalElementNode" "XMLInternalNode"       
## [3] "XMLAbstractNode"

# Métodos disponíveis para a classe.
methods(class = "XMLInternalElementNode")

##  [1] addAttributes       coerce              docName            
##  [4] getEncoding         initialize          processXInclude    
##  [7] readHTMLList        readHTMLTable       readKeyValueDB     
## [10] readSolrDoc         removeAttributes    removeXMLNamespaces
## [13] saveXML             show                slotsFromS3        
## [16] xmlAttrs<-          xmlChildren<-       xmlClone           
## [19] [[                  xmlNamespaces<-     xmlNamespace<-     
## [22] xmlName<-           xmlParent           xmlToDataFrame     
## [25] xmlToS4             xmlValue<-         
## see '?methods' for accessing help and source code

# Mostra o conteúdo.
show(root)

## <root totalResults="67" response="True">
##   <result title="Resident Evil" year="2002" imdbID="tt0120804" type="movie" poster="https://images-na.ssl-images-amazon.com/images/M/MV5BN2Y2MTljNjMtMDRlNi00ZWNhLThmMWItYTlmZjYyZDk4NzYxXkEyXkFqcGdeQXVyNjQ2MjQ5NzM@._V1_SX300.jpg"/>
##   <result title="Resident Evil: Apocalypse" year="2004" imdbID="tt0318627" type="movie" poster="https://images-na.ssl-images-amazon.com/images/M/MV5BMTc1NTUxMzk0Nl5BMl5BanBnXkFtZTcwNDQ1MDIzMw@@._V1_SX300.jpg"/>
##   <result title="Resident Evil: Extinction" year="2007" imdbID="tt0432021" type="movie" poster="https://images-na.ssl-images-amazon.com/images/M/MV5BNDQ0MWI3MmEtMzM0OC00Y2ViLWE4MDItMzNhNmY1ZTdjMWE2XkEyXkFqcGdeQXVyMTQxNzMzNDI@._V1_SX300.jpg"/>
##   <result title="Resident Evil: Afterlife" year="2010" imdbID="tt1220634" type="movie" poster="https://images-na.ssl-images-amazon.com/images/M/MV5BMTkxNzM3OTg5OF5BMl5BanBnXkFtZTcwMDA5MDA2Mw@@._V1_SX300.jpg"/>
##   <result title="Resident Evil: Retribution" year="2012" imdbID="tt1855325" type="movie" poster="https://images-na.ssl-images-amazon.com/images/M/MV5BMTA2NTkwNjUxNTZeQTJeQWpwZ15BbWU3MDE2OTMxMTg@._V1_SX300.jpg"/>
##   <result title="Resident Evil: The Final Chapter" year="2016" imdbID="tt2592614" type="movie" poster="https://images-na.ssl-images-amazon.com/images/M/MV5BMTc0Mzc2OTQ0Ml5BMl5BanBnXkFtZTgwOTQ5MjE4MDI@._V1_SX300.jpg"/>
##   <result title="Resident Evil: Degeneration" year="2008" imdbID="tt1174954" type="movie" poster="https://images-na.ssl-images-amazon.com/images/M/MV5BMTgwMDE4NzcxMl5BMl5BanBnXkFtZTcwNjU1NjcwMg@@._V1_SX300.jpg"/>
##   <result title="Resident Evil: Damnation" year="2012" imdbID="tt1753496" type="movie" poster="https://images-na.ssl-images-amazon.com/images/M/MV5BNzg2ODUxOTIzN15BMl5BanBnXkFtZTcwMDM0NzAzOA@@._V1_SX300.jpg"/>
##   <result title="Resident Evil 4" year="2005" imdbID="tt0397042" type="game" poster="http://ia.media-imdb.com/images/M/MV5BMTU1NjY2MDM4Nl5BMl5BanBnXkFtZTgwMzk0MTU3MDE@._V1_SX300.jpg"/>
##   <result title="Resident Evil 5" year="2009" imdbID="tt0473298" type="game" poster="http://ia.media-imdb.com/images/M/MV5BMTk3MDMzNzMxMV5BMl5BanBnXkFtZTcwNDYxNTMxNg@@._V1_SX300.jpg"/>
## </root>

# Nome do elemento raíz.
xmlName(root)

## [1] "root"

# Quantos filhos (child) possui.
xmlSize(root)

## [1] 10

# Atributos do elemento raíz.
xmlAttrs(root)

## totalResults     response 
##         "67"       "True"

Seleção

Índices positivos e negativos.
Nome do elemento.
Regra lógica.

kiva <- "http://api.kivaws.org/v1/teams/2/lenders.xml"
doc <- xmlParse(kiva)
root <- xmlRoot(doc)

xmlSize(root)

## [1] 2

xmlName(root)

## [1] "response"

# Seleciona o primeiro filho. Qual a diferença?
root[1]

## $paging
## <paging>
##   <page>1</page>
##   <total>68</total>
##   <page_size>50</page_size>
##   <pages>2</pages>
## </paging> 
## 
## attr(,"class")
## [1] "XMLInternalNodeList" "XMLNodeList"

root[[1]]

## <paging>
##   <page>1</page>
##   <total>68</total>
##   <page_size>50</page_size>
##   <pages>2</pages>
## </paging>

# Extraindo o conteúdo do elemento.
xmlValue(root[[1]])

## [1] "168502"

root[[1]]["total"]

## $total
## <total>68</total> 
## 
## attr(,"class")
## [1] "XMLInternalNodeList" "XMLNodeList"

root[[1]][["total"]]

## <total>68</total>

xmlValue(root[[1]][["total"]])

## [1] "68"

Atributos

url <- "http://www.omdbapi.com/?s=%s&r=xml"
url <- sprintf(url, "resident evil")
url

## [1] "http://www.omdbapi.com/?s=resident evil&r=xml"

# browseURL(url)

doc <- xmlParse(url)
docName(doc)

## [1] "http://www.omdbapi.com/?s=resident%20evil&r=xml"

root <- xmlRoot(doc)
xmlName(root)

## [1] "root"

xmlSize(root)

## [1] 10

# Pega os atributos do elemento raíz.
xmlAttrs(root)

## totalResults     response 
##         "67"       "True"

# Nome dos filhos.
names(root)

##   result   result   result   result   result   result   result 
## "result" "result" "result" "result" "result" "result" "result" 
##   result   result   result 
## "result" "result" "result"

# Seleciona o primeiro filho.
root[[1]]

## <result title="Resident Evil" year="2002" imdbID="tt0120804" type="movie" poster="https://images-na.ssl-images-amazon.com/images/M/MV5BN2Y2MTljNjMtMDRlNi00ZWNhLThmMWItYTlmZjYyZDk4NzYxXkEyXkFqcGdeQXVyNjQ2MjQ5NzM@._V1_SX300.jpg"/>

# Extrai todos os atributos.
xmlAttrs(root[[1]])

##                                                                                                                                             title 
##                                                                                                                                   "Resident Evil" 
##                                                                                                                                              year 
##                                                                                                                                            "2002" 
##                                                                                                                                            imdbID 
##                                                                                                                                       "tt0120804" 
##                                                                                                                                              type 
##                                                                                                                                           "movie" 
##                                                                                                                                            poster 
## "https://images-na.ssl-images-amazon.com/images/M/MV5BN2Y2MTljNjMtMDRlNi00ZWNhLThmMWItYTlmZjYyZDk4NzYxXkEyXkFqcGdeQXVyNjQ2MjQ5NzM@._V1_SX300.jpg"

# Extrai apenas o atributo especificado.
xmlGetAttr(root[[1]], name = "title")

## [1] "Resident Evil"

xmlGetAttr(root[[1]], name = "year")

## [1] "2002"

Percorrer a árvore

# Cria uma lista onde cada child (filme) é um elemento da lista.
child <- xmlChildren(root)
str(child)

## List of 10
##  $ result:Classes 'XMLInternalElementNode', 'XMLInternalNode', 'XMLAbstractNode' <externalptr> 
##  $ result:Classes 'XMLInternalElementNode', 'XMLInternalNode', 'XMLAbstractNode' <externalptr> 
##  $ result:Classes 'XMLInternalElementNode', 'XMLInternalNode', 'XMLAbstractNode' <externalptr> 
##  $ result:Classes 'XMLInternalElementNode', 'XMLInternalNode', 'XMLAbstractNode' <externalptr> 
##  $ result:Classes 'XMLInternalElementNode', 'XMLInternalNode', 'XMLAbstractNode' <externalptr> 
##  $ result:Classes 'XMLInternalElementNode', 'XMLInternalNode', 'XMLAbstractNode' <externalptr> 
##  $ result:Classes 'XMLInternalElementNode', 'XMLInternalNode', 'XMLAbstractNode' <externalptr> 
##  $ result:Classes 'XMLInternalElementNode', 'XMLInternalNode', 'XMLAbstractNode' <externalptr> 
##  $ result:Classes 'XMLInternalElementNode', 'XMLInternalNode', 'XMLAbstractNode' <externalptr> 
##  $ result:Classes 'XMLInternalElementNode', 'XMLInternalNode', 'XMLAbstractNode' <externalptr> 
##  - attr(*, "class")= chr [1:2] "XMLInternalNodeList" "XMLNodeList"

f <- function(node) {
    c(title = xmlGetAttr(node, name = "title"),
      year = xmlGetAttr(node, name = "year"))
}

# Aplica uma função em cada elemento da lista.
sapply(child, FUN = f)

##       result          result                     
## title "Resident Evil" "Resident Evil: Apocalypse"
## year  "2002"          "2004"                     
##       result                      result                    
## title "Resident Evil: Extinction" "Resident Evil: Afterlife"
## year  "2007"                      "2010"                    
##       result                      
## title "Resident Evil: Retribution"
## year  "2012"                      
##       result                            
## title "Resident Evil: The Final Chapter"
## year  "2016"                            
##       result                        result                    
## title "Resident Evil: Degeneration" "Resident Evil: Damnation"
## year  "2008"                        "2012"                    
##       result            result           
## title "Resident Evil 4" "Resident Evil 5"
## year  "2005"            "2009"

# xmlApply(x, ...) = lapply(xmlChildren(x), ...)
xmlApply(root, FUN = f)

## $result
##           title            year 
## "Resident Evil"          "2002" 
## 
## $result
##                       title                        year 
## "Resident Evil: Apocalypse"                      "2004" 
## 
## $result
##                       title                        year 
## "Resident Evil: Extinction"                      "2007" 
## 
## $result
##                      title                       year 
## "Resident Evil: Afterlife"                     "2010" 
## 
## $result
##                        title                         year 
## "Resident Evil: Retribution"                       "2012" 
## 
## $result
##                              title 
## "Resident Evil: The Final Chapter" 
##                               year 
##                             "2016" 
## 
## $result
##                         title                          year 
## "Resident Evil: Degeneration"                        "2008" 
## 
## $result
##                      title                       year 
## "Resident Evil: Damnation"                     "2012" 
## 
## $result
##             title              year 
## "Resident Evil 4"            "2005" 
## 
## $result
##             title              year 
## "Resident Evil 5"            "2009"

# xmlSApply(x, ...) = sapply(xmlChildren(x), ...)
# S: simplifica quando possível.
xmlSApply(root, FUN = f)

##       result          result                     
## title "Resident Evil" "Resident Evil: Apocalypse"
## year  "2002"          "2004"                     
##       result                      result                    
## title "Resident Evil: Extinction" "Resident Evil: Afterlife"
## year  "2007"                      "2010"                    
##       result                      
## title "Resident Evil: Retribution"
## year  "2012"                      
##       result                            
## title "Resident Evil: The Final Chapter"
## year  "2016"                            
##       result                        result                    
## title "Resident Evil: Degeneration" "Resident Evil: Damnation"
## year  "2008"                        "2012"                    
##       result            result           
## title "Resident Evil 4" "Resident Evil 5"
## year  "2005"            "2009"

placat <- "https://www.w3schools.com/Xml/plant_catalog.xml"

library(RCurl)
doc <- xmlParse(getURL(placat))
root <- xmlRoot(doc)
xmlSize(root)

## [1] 36

xmlName(root)

## [1] "CATALOG"

names(root)

##   PLANT   PLANT   PLANT   PLANT   PLANT   PLANT   PLANT   PLANT 
## "PLANT" "PLANT" "PLANT" "PLANT" "PLANT" "PLANT" "PLANT" "PLANT" 
##   PLANT   PLANT   PLANT   PLANT   PLANT   PLANT   PLANT   PLANT 
## "PLANT" "PLANT" "PLANT" "PLANT" "PLANT" "PLANT" "PLANT" "PLANT" 
##   PLANT   PLANT   PLANT   PLANT   PLANT   PLANT   PLANT   PLANT 
## "PLANT" "PLANT" "PLANT" "PLANT" "PLANT" "PLANT" "PLANT" "PLANT" 
##   PLANT   PLANT   PLANT   PLANT   PLANT   PLANT   PLANT   PLANT 
## "PLANT" "PLANT" "PLANT" "PLANT" "PLANT" "PLANT" "PLANT" "PLANT" 
##   PLANT   PLANT   PLANT   PLANT 
## "PLANT" "PLANT" "PLANT" "PLANT"

root[[1]]

## <PLANT>
##   <COMMON>Bloodroot</COMMON>
##   <BOTANICAL>Sanguinaria canadensis</BOTANICAL>
##   <ZONE>4</ZONE>
##   <LIGHT>Mostly Shady</LIGHT>
##   <PRICE>$2.44</PRICE>
##   <AVAILABILITY>031599</AVAILABILITY>
## </PLANT>

names(root[[1]])

##         COMMON      BOTANICAL           ZONE          LIGHT 
##       "COMMON"    "BOTANICAL"         "ZONE"        "LIGHT" 
##          PRICE   AVAILABILITY 
##        "PRICE" "AVAILABILITY"

root[[1]][["BOTANICAL"]]

## <BOTANICAL>Sanguinaria canadensis</BOTANICAL>

# xmlSApply(root,
#           FUN = function(node) {
#               node[["PRICE"]]
#           })

# Idem ao código acima comentado.
head(xmlSApply(root, FUN = "[[", "PRICE"))

## $PLANT
## <PRICE>$2.44</PRICE> 
## 
## $PLANT
## <PRICE>$9.37</PRICE> 
## 
## $PLANT
## <PRICE>$6.81</PRICE> 
## 
## $PLANT
## <PRICE>$9.90</PRICE> 
## 
## $PLANT
## <PRICE>$6.44</PRICE> 
## 
## $PLANT
## <PRICE>$9.03</PRICE>

xmlSApply(root,
          FUN = function(node) {
              xmlValue(node[["PRICE"]])
          })

##   PLANT   PLANT   PLANT   PLANT   PLANT   PLANT   PLANT   PLANT 
## "$2.44" "$9.37" "$6.81" "$9.90" "$6.44" "$9.03" "$4.45" "$3.99" 
##   PLANT   PLANT   PLANT   PLANT   PLANT   PLANT   PLANT   PLANT 
## "$3.23" "$2.98" "$2.80" "$5.59" "$6.59" "$3.90" "$3.20" "$9.04" 
##   PLANT   PLANT   PLANT   PLANT   PLANT   PLANT   PLANT   PLANT 
## "$6.94" "$9.58" "$8.86" "$9.16" "$4.59" "$7.16" "$9.80" "$2.57" 
##   PLANT   PLANT   PLANT   PLANT   PLANT   PLANT   PLANT   PLANT 
## "$9.34" "$2.78" "$7.06" "$6.56" "$7.81" "$8.56" "$9.26" "$4.36" 
##   PLANT   PLANT   PLANT   PLANT 
## "$7.89" "$8.60" "$5.63" "$3.02"

Navegando na família

doc <- xmlParse("http://api.kivaws.org/v1/lenders/matt.xml")
summary(doc)

## $nameCounts
## 
##      country_code                id             image 
##                 1                 1                 1 
##     invitee_count            lender         lender_id 
##                 1                 1                 1 
##           lenders      loan_because        loan_count 
##                 1                 1                 1 
##      member_since              name        occupation 
##                 1                 1                 1 
## occupational_info      personal_url          response 
##                 1                 1                 1 
##       template_id               uid       whereabouts 
##                 1                 1                 1 
## 
## $numNodes
## [1] 18

root <- xmlRoot(doc)

lend <- root[["lenders"]][["lender"]]
xmlSize(lend)

## [1] 13

names(lend)

##           lender_id                name               image 
##         "lender_id"              "name"             "image" 
##         whereabouts        country_code                 uid 
##       "whereabouts"      "country_code"               "uid" 
##        member_since        personal_url          occupation 
##      "member_since"      "personal_url"        "occupation" 
##        loan_because   occupational_info          loan_count 
##      "loan_because" "occupational_info"        "loan_count" 
##       invitee_count 
##     "invitee_count"

img <- lend[["image"]]

xmlName(xmlParent(img))

## [1] "lender"

names(xmlChildren(img))

## [1] "id"          "template_id"

xmlName(getSibling(img, after = TRUE))

## [1] "whereabouts"

xmlName(getSibling(img, after = FALSE))

## [1] "name"

Resumo das funções

Função	Classe
`xmlParse`	XMLInternalDocument
`xmlRoot`	XMLInternalElementNode
`[`, `[[`	XMLInternalNodeList

Função	Descrição
`xmlName`	Nome do elemento
`xmlSize`	Número de filhos
`xmlAttrs`	Vetor com os atributos
`xmlGetAttr`	Apenas um atributo pelo nome
`xmlValue`	Conteúdo do elemento
`xmlChildren`	Lista com os filhos
`xmlParent`	Elemento pai

Função	Descrição
`xmlApply`	Aplica função aos filhos de um elemento
`xmlSApply`	Idem, mas simplifica quando possível

Web API são mecanísmos comuns para consumo de dados.
XML e JSON são os formatos mais utilizados pela flexibilidade.
O pacote XML tem recursos para manipulação de documentos XML e derivados.
Foi trabalhado recursos para seleção de elementos, exame, extração de conteúdo e para percorrer elementos em uma árvore.

HTML
Xpath
Sabatina

Manipulação de XML

Objetivo e justificativa

Dados disponíveis em APIs públicas

API WEB

The Open Movie Database

Earthquake Catalog API

Open Weather Map API

Mais APIs

Atenção

Exame e Operação de XML

Dados colhidos da API

O documento XML

Propriedades do elemento root

Seleção

Atributos

Percorrer a árvore

Navegando na família

Resumo das funções

Resumo

Próxima semana

Referências