如何仅对某些字符进行百分比编码答案

【问题标题】：How to percent-encode only some characters如何仅对某些字符进行百分比编码
【发布时间】：2022-10-21 02:45:30
【问题描述】：

SPARQL 函数 ENCODE_FOR_URI 转义输入中除未保留的 URI 字符之外的所有字符。如何更改它以忽略某些（例如用于 IRI 的非 ASCII 字符）字符？

【问题讨论】：

标签： sparql

【解决方案1】：

这是一个非标准解决方案，因为它需要超出 SPARQL 规范要求的额外正则表达式支持（前瞻），但它适用于某些数据集（例如 Wikidata）。这是完整的解决方案：它还需要选择一个不应（也不能）被替换的字符（在这种情况下为_）和输入中不存在的字符（u0000 不能存储在 RDF 中，所以这是一个好选择）

  BIND("0/1&2]3%4@5_" AS ?text)
  BIND(REPLACE(?text, "[^u0001-u005Eu0060-u007F]+", "") AS ?filtered) # the characters to keep
  BIND(REPLACE(?filtered, "(.)(?=.*\1)", "", "s") AS ?shortened) # leaves only one of each character
  BIND(REPLACE(?shortened, "(.)", "_$1", "s") AS ?separated) # separates the characters via _
  BIND(CONCAT(?separated, ENCODE_FOR_URI(?separated)) AS ?encoded) # appends the encoded variant after it
  BIND(CONCAT("_([^_]*)(?=(?:_[^_]*){", STR(STRLEN(?shortened) - 1), "}_([^_]*))?") AS ?regex)
  BIND(REPLACE(?encoded, ?regex, "$1$2u0000", "s") AS ?replaced) # groups the character and replacement together, separated by u0000
  BIND(REPLACE(?shortened, "([-\]\[])", "\\$1") AS ?class) # converts the remaining characters to a valid regex class
  BIND(CONCAT(?text, "u0000", ?replaced) AS ?prepared) # appends the replacement groups after the original text
  BIND(CONCAT("([", ?class, "])(?=.*?u0000\1([^u0000]*))|u0000.*") AS ?regex2)
  BIND(REPLACE(?prepared, ?regex2, "$2", "s") AS ?result) # replaces each occurrence of the character by its replacement in the group at the end

如果您事先知道精确的替换，则只需要最后 3 行来形成字符串。

【讨论】：