Parse response headers

Parse response header data as returned by curl_fetch, either as a set of strings or into a named list.

parse_headers(txt, multiple = FALSE)

parse_headers_list(txt)

Arguments

txt	raw or character vector with the header data
multiple	parse multiple sets of headers separated by a blank line. See details.

Details

The parse_headers_list function parses the headers into a normalized (lowercase field names, trimmed whitespace) named list.

If a request has followed redirects, the data can contain multiple sets of headers. When multiple = TRUE, the function returns a list with the response headers for each request. By default it only returns the headers of the final request.

Examples

req <- curl_fetch_memory("https://httpbin.org/redirect/3")
parse_headers(req$headers)
#>  [1] "HTTP/1.1 200 OK"                            
#>  [2] "Access-Control-Allow-Credentials: true"     
#>  [3] "Access-Control-Allow-Origin: *"             
#>  [4] "Content-Encoding: gzip"                     
#>  [5] "Content-Type: application/json"             
#>  [6] "Date: Mon, 02 Dec 2019 12:01:50 GMT"        
#>  [7] "Referrer-Policy: no-referrer-when-downgrade"
#>  [8] "Server: nginx"                              
#>  [9] "X-Content-Type-Options: nosniff"            
#> [10] "X-Frame-Options: DENY"                      
#> [11] "X-XSS-Protection: 1; mode=block"            
#> [12] "Content-Length: 201"                        
#> [13] "Connection: keep-alive"                     
parse_headers(req$headers, multiple = TRUE)
#> [[1]]
#>  [1] "HTTP/1.1 302 FOUND"                         
#>  [2] "Access-Control-Allow-Credentials: true"     
#>  [3] "Access-Control-Allow-Origin: *"             
#>  [4] "Content-Type: text/html; charset=utf-8"     
#>  [5] "Date: Mon, 02 Dec 2019 12:01:50 GMT"        
#>  [6] "Location: /relative-redirect/2"             
#>  [7] "Referrer-Policy: no-referrer-when-downgrade"
#>  [8] "Server: nginx"                              
#>  [9] "X-Content-Type-Options: nosniff"            
#> [10] "X-Frame-Options: DENY"                      
#> [11] "X-XSS-Protection: 1; mode=block"            
#> [12] "Content-Length: 247"                        
#> [13] "Connection: keep-alive"                     
#> 
#> [[2]]
#>  [1] "HTTP/1.1 302 FOUND"                         
#>  [2] "Access-Control-Allow-Credentials: true"     
#>  [3] "Access-Control-Allow-Origin: *"             
#>  [4] "Content-Type: text/html; charset=utf-8"     
#>  [5] "Date: Mon, 02 Dec 2019 12:01:50 GMT"        
#>  [6] "Location: /relative-redirect/1"             
#>  [7] "Referrer-Policy: no-referrer-when-downgrade"
#>  [8] "Server: nginx"                              
#>  [9] "X-Content-Type-Options: nosniff"            
#> [10] "X-Frame-Options: DENY"                      
#> [11] "X-XSS-Protection: 1; mode=block"            
#> [12] "Content-Length: 0"                          
#> [13] "Connection: keep-alive"                     
#> 
#> [[3]]
#>  [1] "HTTP/1.1 302 FOUND"                         
#>  [2] "Access-Control-Allow-Credentials: true"     
#>  [3] "Access-Control-Allow-Origin: *"             
#>  [4] "Content-Type: text/html; charset=utf-8"     
#>  [5] "Date: Mon, 02 Dec 2019 12:01:50 GMT"        
#>  [6] "Location: /get"                             
#>  [7] "Referrer-Policy: no-referrer-when-downgrade"
#>  [8] "Server: nginx"                              
#>  [9] "X-Content-Type-Options: nosniff"            
#> [10] "X-Frame-Options: DENY"                      
#> [11] "X-XSS-Protection: 1; mode=block"            
#> [12] "Content-Length: 0"                          
#> [13] "Connection: keep-alive"                     
#> 
#> [[4]]
#>  [1] "HTTP/1.1 200 OK"                            
#>  [2] "Access-Control-Allow-Credentials: true"     
#>  [3] "Access-Control-Allow-Origin: *"             
#>  [4] "Content-Encoding: gzip"                     
#>  [5] "Content-Type: application/json"             
#>  [6] "Date: Mon, 02 Dec 2019 12:01:50 GMT"        
#>  [7] "Referrer-Policy: no-referrer-when-downgrade"
#>  [8] "Server: nginx"                              
#>  [9] "X-Content-Type-Options: nosniff"            
#> [10] "X-Frame-Options: DENY"                      
#> [11] "X-XSS-Protection: 1; mode=block"            
#> [12] "Content-Length: 201"                        
#> [13] "Connection: keep-alive"                     
#> 

# Parse into named list
parse_headers_list(req$headers)
#> $`access-control-allow-credentials`
#> [1] "true"
#> 
#> $`access-control-allow-origin`
#> [1] "*"
#> 
#> $`content-encoding`
#> [1] "gzip"
#> 
#> $`content-type`
#> [1] "application/json"
#> 
#> $date
#> [1] "Mon, 02 Dec 2019 12:01:50 GMT"
#> 
#> $`referrer-policy`
#> [1] "no-referrer-when-downgrade"
#> 
#> $server
#> [1] "nginx"
#> 
#> $`x-content-type-options`
#> [1] "nosniff"
#> 
#> $`x-frame-options`
#> [1] "DENY"
#> 
#> $`x-xss-protection`
#> [1] "1; mode=block"
#> 
#> $`content-length`
#> [1] "201"
#> 
#> $connection
#> [1] "keep-alive"
#>