initial docs
This commit is contained in:
		
							
								
								
									
										566
									
								
								docsource/docs/_static/searchtools.js
									
									
									
									
										vendored
									
									
										Normal file
									
								
							
							
						
						
									
										566
									
								
								docsource/docs/_static/searchtools.js
									
									
									
									
										vendored
									
									
										Normal file
									
								
							| @@ -0,0 +1,566 @@ | ||||
| /* | ||||
|  * searchtools.js | ||||
|  * ~~~~~~~~~~~~~~~~ | ||||
|  * | ||||
|  * Sphinx JavaScript utilities for the full-text search. | ||||
|  * | ||||
|  * :copyright: Copyright 2007-2023 by the Sphinx team, see AUTHORS. | ||||
|  * :license: BSD, see LICENSE for details. | ||||
|  * | ||||
|  */ | ||||
| "use strict"; | ||||
|  | ||||
| /** | ||||
|  * Simple result scoring code. | ||||
|  */ | ||||
| if (typeof Scorer === "undefined") { | ||||
|   var Scorer = { | ||||
|     // Implement the following function to further tweak the score for each result | ||||
|     // The function takes a result array [docname, title, anchor, descr, score, filename] | ||||
|     // and returns the new score. | ||||
|     /* | ||||
|     score: result => { | ||||
|       const [docname, title, anchor, descr, score, filename] = result | ||||
|       return score | ||||
|     }, | ||||
|     */ | ||||
|  | ||||
|     // query matches the full name of an object | ||||
|     objNameMatch: 11, | ||||
|     // or matches in the last dotted part of the object name | ||||
|     objPartialMatch: 6, | ||||
|     // Additive scores depending on the priority of the object | ||||
|     objPrio: { | ||||
|       0: 15, // used to be importantResults | ||||
|       1: 5, // used to be objectResults | ||||
|       2: -5, // used to be unimportantResults | ||||
|     }, | ||||
|     //  Used when the priority is not in the mapping. | ||||
|     objPrioDefault: 0, | ||||
|  | ||||
|     // query found in title | ||||
|     title: 15, | ||||
|     partialTitle: 7, | ||||
|     // query found in terms | ||||
|     term: 5, | ||||
|     partialTerm: 2, | ||||
|   }; | ||||
| } | ||||
|  | ||||
| const _removeChildren = (element) => { | ||||
|   while (element && element.lastChild) element.removeChild(element.lastChild); | ||||
| }; | ||||
|  | ||||
| /** | ||||
|  * See https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Regular_Expressions#escaping | ||||
|  */ | ||||
| const _escapeRegExp = (string) => | ||||
|   string.replace(/[.*+\-?^${}()|[\]\\]/g, "\\$&"); // $& means the whole matched string | ||||
|  | ||||
| const _displayItem = (item, searchTerms) => { | ||||
|   const docBuilder = DOCUMENTATION_OPTIONS.BUILDER; | ||||
|   const docUrlRoot = DOCUMENTATION_OPTIONS.URL_ROOT; | ||||
|   const docFileSuffix = DOCUMENTATION_OPTIONS.FILE_SUFFIX; | ||||
|   const docLinkSuffix = DOCUMENTATION_OPTIONS.LINK_SUFFIX; | ||||
|   const showSearchSummary = DOCUMENTATION_OPTIONS.SHOW_SEARCH_SUMMARY; | ||||
|  | ||||
|   const [docName, title, anchor, descr, score, _filename] = item; | ||||
|  | ||||
|   let listItem = document.createElement("li"); | ||||
|   let requestUrl; | ||||
|   let linkUrl; | ||||
|   if (docBuilder === "dirhtml") { | ||||
|     // dirhtml builder | ||||
|     let dirname = docName + "/"; | ||||
|     if (dirname.match(/\/index\/$/)) | ||||
|       dirname = dirname.substring(0, dirname.length - 6); | ||||
|     else if (dirname === "index/") dirname = ""; | ||||
|     requestUrl = docUrlRoot + dirname; | ||||
|     linkUrl = requestUrl; | ||||
|   } else { | ||||
|     // normal html builders | ||||
|     requestUrl = docUrlRoot + docName + docFileSuffix; | ||||
|     linkUrl = docName + docLinkSuffix; | ||||
|   } | ||||
|   let linkEl = listItem.appendChild(document.createElement("a")); | ||||
|   linkEl.href = linkUrl + anchor; | ||||
|   linkEl.dataset.score = score; | ||||
|   linkEl.innerHTML = title; | ||||
|   if (descr) | ||||
|     listItem.appendChild(document.createElement("span")).innerHTML = | ||||
|       " (" + descr + ")"; | ||||
|   else if (showSearchSummary) | ||||
|     fetch(requestUrl) | ||||
|       .then((responseData) => responseData.text()) | ||||
|       .then((data) => { | ||||
|         if (data) | ||||
|           listItem.appendChild( | ||||
|             Search.makeSearchSummary(data, searchTerms) | ||||
|           ); | ||||
|       }); | ||||
|   Search.output.appendChild(listItem); | ||||
| }; | ||||
| const _finishSearch = (resultCount) => { | ||||
|   Search.stopPulse(); | ||||
|   Search.title.innerText = _("Search Results"); | ||||
|   if (!resultCount) | ||||
|     Search.status.innerText = Documentation.gettext( | ||||
|       "Your search did not match any documents. Please make sure that all words are spelled correctly and that you've selected enough categories." | ||||
|     ); | ||||
|   else | ||||
|     Search.status.innerText = _( | ||||
|       `Search finished, found ${resultCount} page(s) matching the search query.` | ||||
|     ); | ||||
| }; | ||||
| const _displayNextItem = ( | ||||
|   results, | ||||
|   resultCount, | ||||
|   searchTerms | ||||
| ) => { | ||||
|   // results left, load the summary and display it | ||||
|   // this is intended to be dynamic (don't sub resultsCount) | ||||
|   if (results.length) { | ||||
|     _displayItem(results.pop(), searchTerms); | ||||
|     setTimeout( | ||||
|       () => _displayNextItem(results, resultCount, searchTerms), | ||||
|       5 | ||||
|     ); | ||||
|   } | ||||
|   // search finished, update title and status message | ||||
|   else _finishSearch(resultCount); | ||||
| }; | ||||
|  | ||||
| /** | ||||
|  * Default splitQuery function. Can be overridden in ``sphinx.search`` with a | ||||
|  * custom function per language. | ||||
|  * | ||||
|  * The regular expression works by splitting the string on consecutive characters | ||||
|  * that are not Unicode letters, numbers, underscores, or emoji characters. | ||||
|  * This is the same as ``\W+`` in Python, preserving the surrogate pair area. | ||||
|  */ | ||||
| if (typeof splitQuery === "undefined") { | ||||
|   var splitQuery = (query) => query | ||||
|       .split(/[^\p{Letter}\p{Number}_\p{Emoji_Presentation}]+/gu) | ||||
|       .filter(term => term)  // remove remaining empty strings | ||||
| } | ||||
|  | ||||
| /** | ||||
|  * Search Module | ||||
|  */ | ||||
| const Search = { | ||||
|   _index: null, | ||||
|   _queued_query: null, | ||||
|   _pulse_status: -1, | ||||
|  | ||||
|   htmlToText: (htmlString) => { | ||||
|     const htmlElement = new DOMParser().parseFromString(htmlString, 'text/html'); | ||||
|     htmlElement.querySelectorAll(".headerlink").forEach((el) => { el.remove() }); | ||||
|     const docContent = htmlElement.querySelector('[role="main"]'); | ||||
|     if (docContent !== undefined) return docContent.textContent; | ||||
|     console.warn( | ||||
|       "Content block not found. Sphinx search tries to obtain it via '[role=main]'. Could you check your theme or template." | ||||
|     ); | ||||
|     return ""; | ||||
|   }, | ||||
|  | ||||
|   init: () => { | ||||
|     const query = new URLSearchParams(window.location.search).get("q"); | ||||
|     document | ||||
|       .querySelectorAll('input[name="q"]') | ||||
|       .forEach((el) => (el.value = query)); | ||||
|     if (query) Search.performSearch(query); | ||||
|   }, | ||||
|  | ||||
|   loadIndex: (url) => | ||||
|     (document.body.appendChild(document.createElement("script")).src = url), | ||||
|  | ||||
|   setIndex: (index) => { | ||||
|     Search._index = index; | ||||
|     if (Search._queued_query !== null) { | ||||
|       const query = Search._queued_query; | ||||
|       Search._queued_query = null; | ||||
|       Search.query(query); | ||||
|     } | ||||
|   }, | ||||
|  | ||||
|   hasIndex: () => Search._index !== null, | ||||
|  | ||||
|   deferQuery: (query) => (Search._queued_query = query), | ||||
|  | ||||
|   stopPulse: () => (Search._pulse_status = -1), | ||||
|  | ||||
|   startPulse: () => { | ||||
|     if (Search._pulse_status >= 0) return; | ||||
|  | ||||
|     const pulse = () => { | ||||
|       Search._pulse_status = (Search._pulse_status + 1) % 4; | ||||
|       Search.dots.innerText = ".".repeat(Search._pulse_status); | ||||
|       if (Search._pulse_status >= 0) window.setTimeout(pulse, 500); | ||||
|     }; | ||||
|     pulse(); | ||||
|   }, | ||||
|  | ||||
|   /** | ||||
|    * perform a search for something (or wait until index is loaded) | ||||
|    */ | ||||
|   performSearch: (query) => { | ||||
|     // create the required interface elements | ||||
|     const searchText = document.createElement("h2"); | ||||
|     searchText.textContent = _("Searching"); | ||||
|     const searchSummary = document.createElement("p"); | ||||
|     searchSummary.classList.add("search-summary"); | ||||
|     searchSummary.innerText = ""; | ||||
|     const searchList = document.createElement("ul"); | ||||
|     searchList.classList.add("search"); | ||||
|  | ||||
|     const out = document.getElementById("search-results"); | ||||
|     Search.title = out.appendChild(searchText); | ||||
|     Search.dots = Search.title.appendChild(document.createElement("span")); | ||||
|     Search.status = out.appendChild(searchSummary); | ||||
|     Search.output = out.appendChild(searchList); | ||||
|  | ||||
|     const searchProgress = document.getElementById("search-progress"); | ||||
|     // Some themes don't use the search progress node | ||||
|     if (searchProgress) { | ||||
|       searchProgress.innerText = _("Preparing search..."); | ||||
|     } | ||||
|     Search.startPulse(); | ||||
|  | ||||
|     // index already loaded, the browser was quick! | ||||
|     if (Search.hasIndex()) Search.query(query); | ||||
|     else Search.deferQuery(query); | ||||
|   }, | ||||
|  | ||||
|   /** | ||||
|    * execute search (requires search index to be loaded) | ||||
|    */ | ||||
|   query: (query) => { | ||||
|     const filenames = Search._index.filenames; | ||||
|     const docNames = Search._index.docnames; | ||||
|     const titles = Search._index.titles; | ||||
|     const allTitles = Search._index.alltitles; | ||||
|     const indexEntries = Search._index.indexentries; | ||||
|  | ||||
|     // stem the search terms and add them to the correct list | ||||
|     const stemmer = new Stemmer(); | ||||
|     const searchTerms = new Set(); | ||||
|     const excludedTerms = new Set(); | ||||
|     const highlightTerms = new Set(); | ||||
|     const objectTerms = new Set(splitQuery(query.toLowerCase().trim())); | ||||
|     splitQuery(query.trim()).forEach((queryTerm) => { | ||||
|       const queryTermLower = queryTerm.toLowerCase(); | ||||
|  | ||||
|       // maybe skip this "word" | ||||
|       // stopwords array is from language_data.js | ||||
|       if ( | ||||
|         stopwords.indexOf(queryTermLower) !== -1 || | ||||
|         queryTerm.match(/^\d+$/) | ||||
|       ) | ||||
|         return; | ||||
|  | ||||
|       // stem the word | ||||
|       let word = stemmer.stemWord(queryTermLower); | ||||
|       // select the correct list | ||||
|       if (word[0] === "-") excludedTerms.add(word.substr(1)); | ||||
|       else { | ||||
|         searchTerms.add(word); | ||||
|         highlightTerms.add(queryTermLower); | ||||
|       } | ||||
|     }); | ||||
|  | ||||
|     if (SPHINX_HIGHLIGHT_ENABLED) {  // set in sphinx_highlight.js | ||||
|       localStorage.setItem("sphinx_highlight_terms", [...highlightTerms].join(" ")) | ||||
|     } | ||||
|  | ||||
|     // console.debug("SEARCH: searching for:"); | ||||
|     // console.info("required: ", [...searchTerms]); | ||||
|     // console.info("excluded: ", [...excludedTerms]); | ||||
|  | ||||
|     // array of [docname, title, anchor, descr, score, filename] | ||||
|     let results = []; | ||||
|     _removeChildren(document.getElementById("search-progress")); | ||||
|  | ||||
|     const queryLower = query.toLowerCase(); | ||||
|     for (const [title, foundTitles] of Object.entries(allTitles)) { | ||||
|       if (title.toLowerCase().includes(queryLower) && (queryLower.length >= title.length/2)) { | ||||
|         for (const [file, id] of foundTitles) { | ||||
|           let score = Math.round(100 * queryLower.length / title.length) | ||||
|           results.push([ | ||||
|             docNames[file], | ||||
|             titles[file] !== title ? `${titles[file]} > ${title}` : title, | ||||
|             id !== null ? "#" + id : "", | ||||
|             null, | ||||
|             score, | ||||
|             filenames[file], | ||||
|           ]); | ||||
|         } | ||||
|       } | ||||
|     } | ||||
|  | ||||
|     // search for explicit entries in index directives | ||||
|     for (const [entry, foundEntries] of Object.entries(indexEntries)) { | ||||
|       if (entry.includes(queryLower) && (queryLower.length >= entry.length/2)) { | ||||
|         for (const [file, id] of foundEntries) { | ||||
|           let score = Math.round(100 * queryLower.length / entry.length) | ||||
|           results.push([ | ||||
|             docNames[file], | ||||
|             titles[file], | ||||
|             id ? "#" + id : "", | ||||
|             null, | ||||
|             score, | ||||
|             filenames[file], | ||||
|           ]); | ||||
|         } | ||||
|       } | ||||
|     } | ||||
|  | ||||
|     // lookup as object | ||||
|     objectTerms.forEach((term) => | ||||
|       results.push(...Search.performObjectSearch(term, objectTerms)) | ||||
|     ); | ||||
|  | ||||
|     // lookup as search terms in fulltext | ||||
|     results.push(...Search.performTermsSearch(searchTerms, excludedTerms)); | ||||
|  | ||||
|     // let the scorer override scores with a custom scoring function | ||||
|     if (Scorer.score) results.forEach((item) => (item[4] = Scorer.score(item))); | ||||
|  | ||||
|     // now sort the results by score (in opposite order of appearance, since the | ||||
|     // display function below uses pop() to retrieve items) and then | ||||
|     // alphabetically | ||||
|     results.sort((a, b) => { | ||||
|       const leftScore = a[4]; | ||||
|       const rightScore = b[4]; | ||||
|       if (leftScore === rightScore) { | ||||
|         // same score: sort alphabetically | ||||
|         const leftTitle = a[1].toLowerCase(); | ||||
|         const rightTitle = b[1].toLowerCase(); | ||||
|         if (leftTitle === rightTitle) return 0; | ||||
|         return leftTitle > rightTitle ? -1 : 1; // inverted is intentional | ||||
|       } | ||||
|       return leftScore > rightScore ? 1 : -1; | ||||
|     }); | ||||
|  | ||||
|     // remove duplicate search results | ||||
|     // note the reversing of results, so that in the case of duplicates, the highest-scoring entry is kept | ||||
|     let seen = new Set(); | ||||
|     results = results.reverse().reduce((acc, result) => { | ||||
|       let resultStr = result.slice(0, 4).concat([result[5]]).map(v => String(v)).join(','); | ||||
|       if (!seen.has(resultStr)) { | ||||
|         acc.push(result); | ||||
|         seen.add(resultStr); | ||||
|       } | ||||
|       return acc; | ||||
|     }, []); | ||||
|  | ||||
|     results = results.reverse(); | ||||
|  | ||||
|     // for debugging | ||||
|     //Search.lastresults = results.slice();  // a copy | ||||
|     // console.info("search results:", Search.lastresults); | ||||
|  | ||||
|     // print the results | ||||
|     _displayNextItem(results, results.length, searchTerms); | ||||
|   }, | ||||
|  | ||||
|   /** | ||||
|    * search for object names | ||||
|    */ | ||||
|   performObjectSearch: (object, objectTerms) => { | ||||
|     const filenames = Search._index.filenames; | ||||
|     const docNames = Search._index.docnames; | ||||
|     const objects = Search._index.objects; | ||||
|     const objNames = Search._index.objnames; | ||||
|     const titles = Search._index.titles; | ||||
|  | ||||
|     const results = []; | ||||
|  | ||||
|     const objectSearchCallback = (prefix, match) => { | ||||
|       const name = match[4] | ||||
|       const fullname = (prefix ? prefix + "." : "") + name; | ||||
|       const fullnameLower = fullname.toLowerCase(); | ||||
|       if (fullnameLower.indexOf(object) < 0) return; | ||||
|  | ||||
|       let score = 0; | ||||
|       const parts = fullnameLower.split("."); | ||||
|  | ||||
|       // check for different match types: exact matches of full name or | ||||
|       // "last name" (i.e. last dotted part) | ||||
|       if (fullnameLower === object || parts.slice(-1)[0] === object) | ||||
|         score += Scorer.objNameMatch; | ||||
|       else if (parts.slice(-1)[0].indexOf(object) > -1) | ||||
|         score += Scorer.objPartialMatch; // matches in last name | ||||
|  | ||||
|       const objName = objNames[match[1]][2]; | ||||
|       const title = titles[match[0]]; | ||||
|  | ||||
|       // If more than one term searched for, we require other words to be | ||||
|       // found in the name/title/description | ||||
|       const otherTerms = new Set(objectTerms); | ||||
|       otherTerms.delete(object); | ||||
|       if (otherTerms.size > 0) { | ||||
|         const haystack = `${prefix} ${name} ${objName} ${title}`.toLowerCase(); | ||||
|         if ( | ||||
|           [...otherTerms].some((otherTerm) => haystack.indexOf(otherTerm) < 0) | ||||
|         ) | ||||
|           return; | ||||
|       } | ||||
|  | ||||
|       let anchor = match[3]; | ||||
|       if (anchor === "") anchor = fullname; | ||||
|       else if (anchor === "-") anchor = objNames[match[1]][1] + "-" + fullname; | ||||
|  | ||||
|       const descr = objName + _(", in ") + title; | ||||
|  | ||||
|       // add custom score for some objects according to scorer | ||||
|       if (Scorer.objPrio.hasOwnProperty(match[2])) | ||||
|         score += Scorer.objPrio[match[2]]; | ||||
|       else score += Scorer.objPrioDefault; | ||||
|  | ||||
|       results.push([ | ||||
|         docNames[match[0]], | ||||
|         fullname, | ||||
|         "#" + anchor, | ||||
|         descr, | ||||
|         score, | ||||
|         filenames[match[0]], | ||||
|       ]); | ||||
|     }; | ||||
|     Object.keys(objects).forEach((prefix) => | ||||
|       objects[prefix].forEach((array) => | ||||
|         objectSearchCallback(prefix, array) | ||||
|       ) | ||||
|     ); | ||||
|     return results; | ||||
|   }, | ||||
|  | ||||
|   /** | ||||
|    * search for full-text terms in the index | ||||
|    */ | ||||
|   performTermsSearch: (searchTerms, excludedTerms) => { | ||||
|     // prepare search | ||||
|     const terms = Search._index.terms; | ||||
|     const titleTerms = Search._index.titleterms; | ||||
|     const filenames = Search._index.filenames; | ||||
|     const docNames = Search._index.docnames; | ||||
|     const titles = Search._index.titles; | ||||
|  | ||||
|     const scoreMap = new Map(); | ||||
|     const fileMap = new Map(); | ||||
|  | ||||
|     // perform the search on the required terms | ||||
|     searchTerms.forEach((word) => { | ||||
|       const files = []; | ||||
|       const arr = [ | ||||
|         { files: terms[word], score: Scorer.term }, | ||||
|         { files: titleTerms[word], score: Scorer.title }, | ||||
|       ]; | ||||
|       // add support for partial matches | ||||
|       if (word.length > 2) { | ||||
|         const escapedWord = _escapeRegExp(word); | ||||
|         Object.keys(terms).forEach((term) => { | ||||
|           if (term.match(escapedWord) && !terms[word]) | ||||
|             arr.push({ files: terms[term], score: Scorer.partialTerm }); | ||||
|         }); | ||||
|         Object.keys(titleTerms).forEach((term) => { | ||||
|           if (term.match(escapedWord) && !titleTerms[word]) | ||||
|             arr.push({ files: titleTerms[word], score: Scorer.partialTitle }); | ||||
|         }); | ||||
|       } | ||||
|  | ||||
|       // no match but word was a required one | ||||
|       if (arr.every((record) => record.files === undefined)) return; | ||||
|  | ||||
|       // found search word in contents | ||||
|       arr.forEach((record) => { | ||||
|         if (record.files === undefined) return; | ||||
|  | ||||
|         let recordFiles = record.files; | ||||
|         if (recordFiles.length === undefined) recordFiles = [recordFiles]; | ||||
|         files.push(...recordFiles); | ||||
|  | ||||
|         // set score for the word in each file | ||||
|         recordFiles.forEach((file) => { | ||||
|           if (!scoreMap.has(file)) scoreMap.set(file, {}); | ||||
|           scoreMap.get(file)[word] = record.score; | ||||
|         }); | ||||
|       }); | ||||
|  | ||||
|       // create the mapping | ||||
|       files.forEach((file) => { | ||||
|         if (fileMap.has(file) && fileMap.get(file).indexOf(word) === -1) | ||||
|           fileMap.get(file).push(word); | ||||
|         else fileMap.set(file, [word]); | ||||
|       }); | ||||
|     }); | ||||
|  | ||||
|     // now check if the files don't contain excluded terms | ||||
|     const results = []; | ||||
|     for (const [file, wordList] of fileMap) { | ||||
|       // check if all requirements are matched | ||||
|  | ||||
|       // as search terms with length < 3 are discarded | ||||
|       const filteredTermCount = [...searchTerms].filter( | ||||
|         (term) => term.length > 2 | ||||
|       ).length; | ||||
|       if ( | ||||
|         wordList.length !== searchTerms.size && | ||||
|         wordList.length !== filteredTermCount | ||||
|       ) | ||||
|         continue; | ||||
|  | ||||
|       // ensure that none of the excluded terms is in the search result | ||||
|       if ( | ||||
|         [...excludedTerms].some( | ||||
|           (term) => | ||||
|             terms[term] === file || | ||||
|             titleTerms[term] === file || | ||||
|             (terms[term] || []).includes(file) || | ||||
|             (titleTerms[term] || []).includes(file) | ||||
|         ) | ||||
|       ) | ||||
|         break; | ||||
|  | ||||
|       // select one (max) score for the file. | ||||
|       const score = Math.max(...wordList.map((w) => scoreMap.get(file)[w])); | ||||
|       // add result to the result list | ||||
|       results.push([ | ||||
|         docNames[file], | ||||
|         titles[file], | ||||
|         "", | ||||
|         null, | ||||
|         score, | ||||
|         filenames[file], | ||||
|       ]); | ||||
|     } | ||||
|     return results; | ||||
|   }, | ||||
|  | ||||
|   /** | ||||
|    * helper function to return a node containing the | ||||
|    * search summary for a given text. keywords is a list | ||||
|    * of stemmed words. | ||||
|    */ | ||||
|   makeSearchSummary: (htmlText, keywords) => { | ||||
|     const text = Search.htmlToText(htmlText); | ||||
|     if (text === "") return null; | ||||
|  | ||||
|     const textLower = text.toLowerCase(); | ||||
|     const actualStartPosition = [...keywords] | ||||
|       .map((k) => textLower.indexOf(k.toLowerCase())) | ||||
|       .filter((i) => i > -1) | ||||
|       .slice(-1)[0]; | ||||
|     const startWithContext = Math.max(actualStartPosition - 120, 0); | ||||
|  | ||||
|     const top = startWithContext === 0 ? "" : "..."; | ||||
|     const tail = startWithContext + 240 < text.length ? "..." : ""; | ||||
|  | ||||
|     let summary = document.createElement("p"); | ||||
|     summary.classList.add("context"); | ||||
|     summary.textContent = top + text.substr(startWithContext, 240).trim() + tail; | ||||
|  | ||||
|     return summary; | ||||
|   }, | ||||
| }; | ||||
|  | ||||
| _ready(Search.init); | ||||
		Reference in New Issue
	
	Block a user