[http] Use POST method only if the form parameter list is non-empty

An attempt to use an existent but empty form parameter list will
currently result in an invalid POST request since the Content-Length
header will be missing.

Fix by using GET instead of POST if the form parameter list is empty.
This is a non-breaking change (since the current behaviour produces an
invalid request), and simplifies the imminent generalisation of the
parameter list concept to handle both header and form parameters.

Signed-off-by: Michael Brown <mcb30@ipxe.org>

diff --git a/src/net/tcp/httpcore.c b/src/net/tcp/httpcore.c
index fd94b5f083e2ba19158e2f665138c4e99292ba19..c970d54bfa98965786820c947b57bd4ddeb67734 100644 (file)
--- a/src/net/tcp/httpcore.c
+++ b/src/net/tcp/httpcore.c
@@ -1904,53 +1904,58 @@ static size_t http_params ( struct parameters *params, char *buf, size_t len ) {
 }
 
 /**
- * Open HTTP transaction for simple GET URI
- *
- * @v xfer             Data transfer interface
- * @v uri              Request URI
- * @ret rc             Return status code
- */
-static int http_open_get_uri ( struct interface *xfer, struct uri *uri ) {
-
-       return http_open ( xfer, &http_get, uri, NULL, NULL );
-}
-
-/**
- * Open HTTP transaction for simple POST URI
+ * Open HTTP transaction for simple URI
  *
  * @v xfer             Data transfer interface
  * @v uri              Request URI
  * @ret rc             Return status code
  */
-static int http_open_post_uri ( struct interface *xfer, struct uri *uri ) {
+int http_open_uri ( struct interface *xfer, struct uri *uri ) {
        struct parameters *params = uri->params;
        struct http_request_content content;
+       struct http_method *method;
+       const char *type;
        void *data;
        size_t len;
        size_t check_len;
        int rc;
 
-       /* Calculate length of parameter list */
-       len = http_params ( params, NULL, 0 );
+       /* Calculate length of parameter list, if any */
+       len = ( params ? http_params ( params, NULL, 0 ) : 0 );
 
-       /* Allocate temporary parameter list */
-       data = zalloc ( len + 1 /* NUL */ );
-       if ( ! data ) {
-               rc = -ENOMEM;
-               goto err_alloc;
-       }
+       /* Use POST if and only if there are parameters */
+       if ( len ) {
 
-       /* Construct temporary parameter list */
-       check_len = http_params ( params, data, ( len + 1 /* NUL */ ) );
-       assert ( check_len == len );
+               /* Use POST */
+               method = &http_post;
+               type = "application/x-www-form-urlencoded";
+
+               /* Allocate temporary parameter list */
+               data = zalloc ( len + 1 /* NUL */ );
+               if ( ! data ) {
+                       rc = -ENOMEM;
+                       goto err_alloc;
+               }
+
+               /* Construct temporary parameter list */
+               check_len = http_params ( params, data, ( len + 1 /* NUL */ ) );
+               assert ( check_len == len );
+
+       } else {
+
+               /* Use GET */
+               method = &http_get;
+               type = NULL;
+               data = NULL;
+       }
 
        /* Construct request content */
-       content.type = "application/x-www-form-urlencoded";
+       content.type = type;
        content.data = data;
        content.len = len;
 
        /* Open HTTP transaction */
-       if ( ( rc = http_open ( xfer, &http_post, uri, NULL, &content ) ) != 0 )
+       if ( ( rc = http_open ( xfer, method, uri, NULL, &content ) ) != 0 )
                goto err_open;
 
  err_open:
@@ -1959,23 +1964,6 @@ static int http_open_post_uri ( struct interface *xfer, struct uri *uri ) {
        return rc;
 }
 
-/**
- * Open HTTP transaction for simple URI
- *
- * @v xfer             Data transfer interface
- * @v uri              Request URI
- * @ret rc             Return status code
- */
-int http_open_uri ( struct interface *xfer, struct uri *uri ) {
-
-       /* Open GET/POST URI as applicable */
-       if ( uri->params ) {
-               return http_open_post_uri ( xfer, uri );
-       } else {
-               return http_open_get_uri ( xfer, uri );
-       }
-}
-
 /* Drag in HTTP extensions */
 REQUIRING_SYMBOL ( http_open );
 REQUIRE_OBJECT ( config_http );