How to label a path drawn using tikz with \draw plot?

Question

Is there any workaround to use [pos=] or [midway] option in a node following a "plot" to annotate the path? The following minimal example will have the node text missing:

\documentclass{article}
\usepackage{tikz}

\begin{document}
\begin{tikzpicture}
    \draw[very thin,color=gray] (-0.1,-0.1) grid (2.9,4.1);
    \draw[->] (-0.2,0) -- (3.2,0) node[right] {$x$};
    \draw[->] (0,-0.2) -- (0,4.2) node[above] {$f(x)$};

    \draw[domain=0:3] plot (\x,{\x^2}) node[midway, sloped] {midway?};
\end{tikzpicture}
\end{document}

Answer 1

I forgot decoration

last version

\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{decorations.markings}

\begin{document}

\begin{tikzpicture}[domain=0:2,label/.style={%
   postaction={ decorate,transform shape,
   decoration={ markings, mark=at position .5 with \node #1;}}}]
\draw[very thin,color=gray] (-0.1,-1.1) grid (3.9,3.9); 

\draw[red,label={[above]{$f(x)=x^2$}}] plot(\x,{\x^2}) ;     

\end{tikzpicture}
\end{document}