How to update headers

update.R

``` r
library("magrittr")
homogeneize <- function(path){
  path %>%
    readLines(encoding = "UTF-8") %>%
    blogdown:::split_yaml_body() %>%
    .$body %>%
    commonmark::markdown_xml(extensions = TRUE) %>%
    xml2::read_xml() -> post_xml
  
  headers <- post_xml %>%
    xml2::xml_find_all(xpath = './/d1:heading', 
                       xml2::xml_ns(.))
  
  levels <-  xml2::xml_attr(headers, "level") %>%
    as.character() %>%
    as.numeric()
  
  no_levels <- length(unique(levels))
  
  if(no_levels == 1){
    xml2::xml_set_attr(headers, "level", "1")
  }
  
  if(no_levels == 2){
    headers1 <- headers[xml2::xml_attr(headers, "level") == min(levels)]
    xml2::xml_set_attr(headers1, "level", "1")
    
    headers2 <- headers[xml2::xml_attr(headers, "level") == max(levels)]
    xml2::xml_set_attr(headers2, "level", "2")
  }
  
  if(no_levels == 3){
    headers1 <- headers[xml2::xml_attr(headers, "level") == min(levels)]
    xml2::xml_set_attr(headers1, "level", "1")
    
    headers3 <- headers[xml2::xml_attr(headers, "level") == max(levels)]
    xml2::xml_set_attr(headers3, "level", "3")

    headers2 <- headers[xml2::xml_attr(headers, "level") == (min(levels)+1)]
    xml2::xml_set_attr(headers2, "level", "2")
  }
  
  #missing step converting back to Markdown
  post_xml
}


roblog <- "C:\\Users\\Maelle\\Documents\\ropensci\\roweb2\\content\\blog"

file.path(roblog, "2013-03-08-ropensci-collaboration.md") %>%
  homogeneize() %>%
  xml2::xml_find_all(xpath = './/d1:heading', 
                     xml2::xml_ns(.))
#> {xml_nodeset (5)}
#> [1] <heading level="1">\n  <text>Install some functions for interacting  ...
#> [2] <heading level="1">\n  <text>Get all repos for an organization, here ...
#> [3] <heading level="1">\n  <text>Get commits broken down in to additions ...
#> [4] <heading level="1">\n  <text>Plot commits by date and repo</text>\n< ...
#> [5] <heading level="1">\n  <text>In addition, there are quite a few peop ...


file.path(roblog, "2017-09-27-rrricanes.md") %>%
  homogeneize() %>%
  xml2::xml_find_all(xpath = './/d1:heading', 
                     xml2::xml_ns(.)) %>%
  xml2::xml_attr("level")
#>  [1] "1" "2" "2" "2" "2" "2" "2" "1" "2" "1" "1" "2" "2" "1" "1" "2" "2"
#> [18] "2" "2" "2" "2" "3" "2" "2" "2" "2" "1" "1" "1" "1"

file.path(roblog, "2014-02-19-taxize-update.md") %>%
  homogeneize() %>%
  xml2::xml_find_all(xpath = './/d1:heading', 
                     xml2::xml_ns(.)) 
#> {xml_nodeset (5)}
#> [1] <heading level="1">\n  <text>First, install and load taxize</text>\n ...
#> [2] <heading level="1">\n  <text>New things</text>\n</heading>
#> [3] <heading level="2">\n  <text>New functions: class2tree</text>\n</hea ...
#> [4] <heading level="2">\n  <text>New functions: get_gbfid</text>\n</head ...
#> [5] <heading level="2">\n  <text>New functions: rbind and cbind for clas ...
```

Created on 2018-08-29 by the [reprex package](http://reprex.tidyverse.org) (v0.2.0).