Backward search in ipython via FZF

Question

The question is how can i use fzf for backward search in IPython shell?

Answer 1

1. pip install pyfzf
2. Put the following lines into your ipython startup file, say, any random file located in ~/.ipython/profile_default/startup/
3. Press Ctrl-R in ipython, and you are easy to go.

from prompt_toolkit.enums import DEFAULT_BUFFER                                                                                                                                   
from prompt_toolkit.keys import Keys                                                                                                                                              
from prompt_toolkit.filters import HasFocus, HasSelection                                                                                                                         
try:                                                                                                                                                                              
    from pyfzf import pyfzf                                                                                                                                                       
except:                                                                                                                                                                           
    print("pyfzf is not installed. Please install to enable fzf Ctrl-R search")                                                       

    exit()                                                                                                                                                                        
                                                                                                                                                                                  
ipython = get_ipython()                                                                                                                                                           
fzf = pyfzf.FzfPrompt()                                                                                                                                                           
                                                                                                                                                                                  
def is_in_empty_line(buf):                                                                                                                                                        
    text = buf.text                                                                                                                                                               
    cursor_position = buf.cursor_position                                                                                                                                         
    text = text.split('\n')                                                                                                                                                       
    for line in text:                                                                                                                                                             
        if len(line) >= cursor_position:                                                                                                                                          
            return not line                                                                                                                                                       
        else:                                                                                                                                                                     
            cursor_position -= len(line) + 1                                                                                                                                      
                                                                                                                                                                                  
def fzf_i_search(event):                                                                                                                                                          
    history_set = set()                                                                                                                                                           
    history_strings = [i[2] for i in ipython.history_manager.get_tail(5000)][::-1]                         

    history_strings = [s for s in history_strings if not (s in history_set or history_set.add(s))]                                   

    # refresh prompt                                                                                                                                                              
    print("", end="\r", flush=True)                                                                                                                                               
    try:                                                                                                                                                                          
        text = fzf.prompt(history_strings, fzf_options='--no-sort --multi --reverse')                                                                                             
    except:                                                                                                                                                                       
        return                                                                                                                                                                    
    buf = event.current_buffer                                                                                                                                                    
    if not is_in_empty_line(buf):                                                                                                                                                 
        buf.insert_line_below()                                                                                                                                                   
    buf.insert_text('\n'.join(text))                                                                                                                                              
                                                                                                                                                                                  
# Register the shortcut if IPython is using prompt_toolkit                                                                                                                        
if getattr(ipython, 'pt_app', None):                                                                                                                                              
    registry = ipython.pt_app.key_bindings                                                                                                                                        
    registry.add_binding(Keys.ControlR,                                                                                                                                           
                     filter=(HasFocus(DEFAULT_BUFFER)                                                                                                                             
                             & ~HasSelection()))(fzf_i_search)                                                                                                                    
                                                                                                                                                                                  
del DEFAULT_BUFFER, Keys, HasFocus, HasSelection                                                                                                                                  
del fzf_i_search

Answer 2

Adding to the answer of @SleepyBag, one can add a couple of improvements. fzf does only selection per line, however code-entry in ipython often consistes of several (indented) lines. So this changed code for fzf replace the newlines with @@ for the fuzzy search to allow for selecting multi-line content. It also adds a preview window with syntax highlighting using bat. For that just replace the fzf_i_search`function with

def fzf_i_search(event):
    history_set = set()
    history_strings = [i[2] for i in ipython.history_manager.get_tail(5000)][::-1]

    # we replace newlines as fzf can only work on single lines; in the preview and later
    # we reverse this effect
    history_strings = [
        s.replace("\n", " @@ ")
        for s in history_strings
        if not (s in history_set or history_set.add(s))
    ]

    # refresh prompt
    print("", end="\r", flush=True)
    try:
        text = fzf.prompt(
            history_strings,
            fzf_options="--no-sort --multi --border --height=80% --margin=1 --padding=1"
            " --preview 'echo {} | sed \"s/ @@ /\\n/g\" | bat --color=always --style=numbers -l py -'",
        )
        # multiple returns get concatenated with an emtpy line in-between
        text = "\n\n".join(text)
        # reverse the replacement of newlines
        text = text.replace(" @@ ", "\n")
    except:
        return
    buf = event.current_buffer
    if not is_in_empty_line(buf):
        buf.insert_line_below()
    buf.insert_text(text)